Childhood Gender-Typed Behavior and Adolescent Sexual Orientation: A Longitudinal Population-Based Study

Abstract

Lesbian and gay individuals have been reported to show more interest in other-sex, and/or less interest in same-sex, toys, playmates, and activities in childhood than heterosexual counterparts. Yet, most of the relevant evidence comes from retrospective studies or from prospective studies of clinically referred, extremely gender nonconforming children. In addition, findings are mixed regarding the relation between childhood gender-typed behavior and the later sexual orientation spectrum from exclusively heterosexual to exclusively lesbian/gay. The current study drew a sample (2,428 girls and 2,169 boys) from a population-based longitudinal study, and found that the levels of gender-typed behavior at ages 3.5 and 4.75 years, although less so at age 2.5 years, significantly and consistently predicted adolescents' sexual orientation at age 15 years, both when sexual orientation was conceptualized as 2 groups or as a spectrum. In addition, within-individual change in gender-typed behavior during the preschool years significantly related to adolescent sexual orientation, especially in boys. These results suggest that the factors contributing to the link between childhood gender-typed behavior and sexual orientation emerge during early development. Some of those factors are likely to be nonsocial, because nonheterosexual individuals appear to diverge from gender norms regardless of social encouragement to conform to gender roles. (PsycINFO Database Record)

Full text

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 1
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Childhood Gender-Typed Behavior and Adolescent Sexual Orientation:
A Longitudinal Population-Based Study
Gu Li, Karson T. F. Kung, and Melissa Hines
University of Cambridge
Author Note
Gu Li, Karson T. F. Kung, and Melissa Hines, Department of Psychology, University
of Cambridge.
We are extremely grateful to all the families who took part in this study, the midwives
for their help in recruiting them, and the whole ALSPAC team, which includes interviewers,
computer and laboratory technicians, clerical workers, research scientists, volunteers,
managers, receptionists, and nurses. The UK Medical Research Council and the Wellcome
Trust (Grant ref: 102215/2/13/2) and the University of Bristol provide core support for
ALSPAC. This publication is the work of the authors and Gu Li will serve as guarantor for
the contents of this paper. This specific study was supported by a Cambridge International
Scholarship awarded to Gu Li and by research funding from the Department of Psychology,
University of Cambridge.
Correspondence concerning this article should be addressed to Gu Li, Department of
Psychology, University of Cambridge, Free School Lane, Cambridge CB2 3RQ, UK. E-mail:
gl369@cam.ac.uk

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 2
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This manuscript was accepted for publication in Developmental Psychology on November 17,
2016. This is the accepted author manuscript. APA’s final edited version of this article is
available online on February 20, 2017 at http://dx.doi.org/10.1037/dev0000281

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 3
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Abstract
Lesbian and gay individuals have been reported to show more interest in other-sex, and/or
less interest in same-sex, toys, playmates, and activities in childhood than heterosexual
counterparts. Yet, most of the relevant evidence comes from retrospective studies or from
prospective studies of clinically-referred, extremely gender nonconforming children. In
addition, findings are mixed regarding the relationship between childhood gender-typed
behavior and the later sexual orientation spectrum from exclusively heterosexual to
exclusively lesbian/gay. The current study drew a sample (2,428 girls and 2,169 boys) from a
population-based longitudinal study, and found that the levels of gender-typed behavior at
ages 3.50 and 4.75 years, although less so at age 2.50 years, significantly and consistently
predicted adolescents’ sexual orientation at age 15 years, both when sexual orientation was
conceptualized as two groups or as a spectrum. In addition, within-individual change in
gender-typed behavior during the preschool years significantly related to adolescent sexual
orientation, especially in boys. These results suggest that the factors contributing to the link
between childhood gender-typed behavior and sexual orientation emerge during early
development. Some of those factors are likely to be nonsocial, because nonheterosexual
individuals appear to diverge from gender norms regardless of social encouragement to
conform to gender roles.
Keywords: gender nonconformity, sexual orientation, gender-typed behavior, LGB,
ALSPAC

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 4
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Childhood Gender-Typed Behavior and Adolescent Sexual Orientation:
A Longitudinal Population-Based Study
Childhood gender-typed behavior is perhaps the most extensively studied early
behavioral predictor of sexual orientation. Gender-typed behavior, or gender role behavior,
refers to behaviors, attitudes, and personality traits that differ on average for females and
males (Hines, 2004). Among children, gender-typed behavior can be observed in preferences
for male-typical or female-typical toys (e.g., toy trucks versus dolls), playmates (e.g., boys
versus girls), and play activities (e.g., rough-and-tumble play versus playing house)
(Golomok & Rust, 1993a, 1993b; Maccoby & Jacklin, 1974; Martin, Eisenbud, & Rose,
1995). Childhood gender-typed behavior shows a large sex difference and has been
considered as an important component of human gender development (Hines, 2010, 2015).
Another domain of gender development that differs substantially between males and
females is sexual orientation (Hines, 2010, 2011). Sexual orientation directs a person’s
sexuality to men, to women, to both, or to neither; it can be measured using multiple
indicators such as romantic and sexual attraction, sexual behavior, sexual identity, and
physiological sexual arousal (Bailey et al., 2016; Savin-Williams, 2006). Sexual orientation is
manifested in adolescence by ages 12–17 years (Calzo, Masyn, Austin, Jun, & Corliss, 2016;
Russell & Fish, 2016), and may be seen in children as young as 10 years of age (McClintock
& Herdt, 1996). During adolescence, the most observable indicators of sexual orientation are
sexual attraction and perhaps some sexual activities such as kissing on the mouth (Calzo,
Antonucci, Mays, & Cochran, 2011; D’Augelli, Grossman, Starks, & Sinclair, 2010; Li &
Hines, 2016; McClintock & Herdt, 1996; Rosario et al., 1996; Savin-Williams & Diamond,
2000). Theoretical perspectives and empirical research suggest that individuals with different
sexual orientations may show different childhood gender-typed behaviors.
Theoretical Perspectives

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 5
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Both genetic and hormonal theories suggest a link between childhood gender-typed
behavior and sexual orientation. Genes are suggested to influence childhood gender-typed
behavior (e.g., Iervolino, Hines, Golombok, Rust, & Plomin, 2005; Knafo, Iervolino, &
Plomin, 2005) and (male) sexual orientation (e.g., Sanders et al., 2015; see also Bailey et al.,
2016, for a review), and it is possible that some common genes contribute to both of these
domains. Twin studies suggest that additive genetic factors account for a modest to
substantial amount of the covariance between recalled childhood gender-typed behavior and
sexual orientation in women (Alanko et al., 2010; Bailey, Dunne, & Martin, 2000; Burri,
Cherkas, Spector, & Rahman, 2011) and in men (Alanko et al., 2010; Bailey et al., 2000).
Early androgen exposure may also contribute to the development of both childhood
gender-typed behavior and sexual orientation (Hines, 2011). Substantial evidence suggests
that androgen exposure during prenatal and neonatal periods contributes to enduring sex
differences in the mammalian brain and behavior (Arnold, 2009; Hines et al., 2016;
McCarthy & Arnold, 2011; Morris, Jordan, & Breedlove, 2004). In nonhuman animals,
numerous experiments have demonstrated that administration of androgens during early
development masculinizes and/or defeminizes later sexual behaviors, as well as other
behaviors that differ on average for males and females (Arnold, 2009; Hines, 2004, 2011). In
humans, the strongest empirical support for influences of early androgens on gender
development comes from research involving females with congenital adrenal hyperplasia
(CAH), a recessive autosomal condition that results in increased exposure to testosterone and
other androgens, beginning before birth (New, 1998). A number of studies have reported that,
compared to unaffected relatives and to matched controls, females with CAH show increased
male-typical behavior in childhood, as well as increased nonheterosexual fantasy and
behavior in adulthood (Hines, 2011). There is also some evidence that normal variability in
androgen exposure relates to childhood gender-typed behavior in typically-developing

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children (Hines et al., 2002; Lamminmäki et al., 2012; Pasterski et al., 2015). However, little
is known about the influences of early androgen exposure on sexual orientation in typically-
developing individuals, perhaps due to the difficulty in measuring early androgen
concentrations reliably and accurately in a sufficiently large sample, and following the
sample into adolescence (e.g., Hines et al., 2002; Hines, Constantinescu, & Spencer, 2015).
Research on Childhood Gender-Typed Behavior and Sexual Orientation
The majority of past studies comparing childhood gender-typed behavior in
individuals with different sexual orientations are retrospective. These studies, more than 60 in
total, consistently reported that lesbian women and gay men recalled significantly more
gender nonconforming behavior than heterosexual counterparts (reviewed in Bailey &
Zucker, 1995; Zucker, 2008). Bailey and Zucker estimated that the magnitude of the
difference was large, with an overall Cohen’s d of 1.3 for men and of 1.0 for women; by
Cohen’s (1988) recommendation, d values of 0.2, 0.5, and 0.8 represent small, medium, and
large effects, respectively.
Despite these consistent findings, retrospective studies can be criticized as susceptible
to memory bias (e.g., Ross, 1980; Gottschalk, 2003). In response to this potential concern,
Rieger, Linsenmeier, Gygax, and Bailey (2008) collected lesbian/gay and heterosexual
adults’ childhood home videos and had their childhood gender-typed behavior evaluated by
independent raters who watched the videos and coded the gender-typicality of the behaviors
shown. They observed a large and significant overall difference (ds = 1.0 for men and 1.2 for
women) in the rated childhood gender-typed behavior between the two sexual orientation
groups, suggesting that the difference is more than a product of memory bias.
Another line of evidence supporting the link between childhood gender-typed
behavior and later sexual orientation comes from clinically referred children, many of whom
demonstrate extreme cross-gender behavior that partially or fully meets the diagnostic criteria

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 7
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for gender dysphoria/gender identity disorder in the Diagnostic and Statistical Manual of
Mental Disorders (American Psychiatric Association, 2000, 2013). Across 11 such studies,
over 30% of extremely gender nonconforming girls and over 60% of extremely gender
nonconforming boys reported some same- or both-sex sexual fantasy or behavior in
adolescence or adulthood (Drummond, Bradley, Peterson-Badali, & Zucker, 2008; Green,
1987; Singh, 2012; Wallien & Cohen-Kettenis, 2008; also see Zucker & Bradley, 1995 for a
summary of another 6 studies). These percentages exceed similar figures for same- or both-
sex sexual fantasy or behavior in the general population (estimated as 3% of women and men;
summarized from Figure 1 in Bailey et al., 2016), especially for men. Even if individuals in
the general population who are mostly heterosexual are included, the prevalence rates of
nonheterosexual women and men are 13% and 7% respectively, still lower than the 30% and
60% figures for extremely gender nonconforming girls and boys who would become
nonheterosexual. However, because these findings are based on clinical samples, it is
unknown how well they apply to the general population.
To date, only one prospective study has analyzed the relation between childhood
gender-typed behavior and later sexual orientation in a general-population sample (Steensma,
van der Ende, Verhulst, & Cohen-Kettenis, 2013). This study included a sample of 473 girls
and 406 boys. Among these participants, 41 girls and 10 boys were classified as gender
nonconforming in childhood based on a single administration of a parent-reported measure
when the participants were 4 to 11 years old. When followed up in adulthood, gender
nonconforming girls were up to 11 times as likely to report nonheterosexuality as all girls,
and gender nonconforming boys were up to 13 times as likely to report nonheterosexuality as
all boys. Taken together, converging evidence from retrospective and prospective research
suggests that, on average, nonheterosexual men and women are more gender nonconforming
during childhood compared to their same-sex heterosexual peers.

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 8
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Despite much theoretical and empirical work, several gaps remain. First, most prior
studies linking childhood gender-typed behavior to sexual orientation were either
retrospective or based on clinical samples, and both of these types of studies have limitations.
Further, the reliability of the results from the one prior longitudinal population-based study
might be limited by the use of a 2-item measure of childhood gender nonconformity, which
showed weak internal consistency (a = .41), and by the small number of gender
nonconforming children, especially boys (Steensma et al., 2013). Therefore, more
prospective research, using a large sample from the general population and more reliable
measures of childhood gender-typed behavior and sexual orientation, is needed.
Second, the age at which any behavioral differences between lesbian/gay and
heterosexual individuals emerge is unknown. Rieger et al. (2008) estimated, in their study of
home videos, that the difference appeared to manifest at around age 3 years, and that it
appeared to become increasingly pronounced from early to late childhood. The possible
developmental increase in the predictive power of gender nonconforming behavior resembles
the development of gender-typed behavior more generally (Golombok et al., 2008;
Golombok & Hines, 2002; Hines, 2015; Maccoby, 1988; Wong & Hines, 2015). The early
emergence of gender-typed behavior suggests that the factors affecting gender-typed
behavior and sexual orientation may come into play before the preschool years. As a
consequence, it would be useful to examine the age trend in a longitudinal population-based
study.
Third, few studies have evaluated relations between childhood gender-typed behavior
and nonexclusive attractions (e.g., mostly heterosexual, bisexual, and mostly lesbian/gay),
although nonexclusively attracted individuals outnumber exclusively lesbian/gay individuals
and comprise the majority of sexual minorities (Diamond, Bonner, & Dickenson, 2015;
Savin-Williams, 2014, 2016; Savin-Williams & Vrangalova, 2013). In other words, while

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 9
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there is a consistent mean difference between lesbian/gay and heterosexual individuals, it is
not clear if there is a monotonic increase in childhood gender nonconforming behavior across
the sexual orientation spectrum from exclusively heterosexual to exclusively lesbian/gay.
Previous research has yielded mixed findings. While some studies have reported a significant
linear relation between childhood gender-typed behavior and later position on the sexual
orientation spectrum (Alanko et al., 2010; Burri et al., 2011; Dunne, Bailey, Kirk, & Martin,
2000; Roberts, Rosario, Corliss, Koenen, & Austin, 2012), others have not (Cardoso, 2009;
Steensma et al., 2013). Notably, the studies that reported a significant linear association had
more participants (Ns > 3,000) than the other studies (Ns < 900), resulting in larger samples
of each sexual orientation group and perhaps a more accurate estimate of the relation. In
addition, most of these studies were retrospective, and so could be affected by biased recall.
The Current Study
The current study addresses these gaps in knowledge using a large sample from a
prospective cohort study in England. This study assessed children’s gender-typed behavior
using a standardized measure, at three ages during the preschool period. These three time
points allowed investigation of the age at which any difference related to sexual orientation
might emerge. Repeated measurement also allowed us to investigate for the first time if
within-individual change in gender-typed behavior over time during the preschool years
predicted sexual orientation. Sexual orientation was primarily self-reported in reference to
relative sexual attraction to same- and other-sex peers at age 15 years. In addition, same- and
other-sex sexual activities were assessed as secondary indicators of adolescent sexual
orientation at age 15 years.
Three questions were addressed using these data. First, do lesbian/gay adolescents
show different levels of gender-typed behavior in childhood than heterosexual counterparts,
and at what age does this difference emerge? Second, is there a monotonic relation between

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 10
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the levels of childhood gender-typed behavior and later positions on the sexual orientation
spectrum? Third, how does change in childhood gender-typed behavior over the preschool
years relate to adolescent sexual orientation?
Method
Participants
The Avon Longitudinal Study of Parents and Children (ALSPAC) is a prospective
study that recruited pregnant women who were scheduled to give birth between April 1, 1991
and December 31, 1992 in a geographically defined area in Avon, Southwest England. The
eligible child cohort, including 1-year live births but excluding one random individual per
twin pair and all triplets and quadruplets according to ALSPAC regulations, consists of 7,065
girls and 7,433 boys. About 80% of the ALSPAC families lived in owner occupied
accommodation, 91% had a car, 79% were married couples, and 2% were non-White.
Compared to the 1991 UK Census data, the ALSPAC sample is slightly more affluent and
less likely to be non-White. For additional information about the ALSPAC cohort, see Boyd
et al. (2013). The study website contains details of all the data, which are available through a
fully searchable data dictionary: http://www.bris.ac.uk/alspac/researchers/data-access/data-
dictionary/. Ethical approval for the study was obtained from the ALSPAC Ethics and Law
Committee and the Local Research Ethics Committees.
The current study analyzed ALSPAC data using four time points, when the children
were 2.50, 3.50, 4.75, and 15 years of age. The participation rate at each time point was 74%,
71%, 65%, and 36%, respectively. Children who had at least one valid assessment of
childhood gender-typed behavior at the first three time points and a valid response of sexual
orientation at the fourth time point were included in this study, N = 4,597 (2,428 girls and
2,169 boys), representing 32% of the eligible ALSPAC child cohort. Girls were more likely
to be included in the current study (34%) compared to boys (29%), χ2(1, n = 14498) = 44.75

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 11
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(with Yates’s correction of continuity), p < .001, and so were White than non-White families
(37% vs. 30%, respectively), χ2(1, n = 11923) = 15.25 (with Yates’s correction of continuity),
p < .001.
Measures
Childhood gender-typed behavior. Caregivers (usually the child’s mother)
evaluated the child’s gender-typed behavior using the Preschool Activities Inventory (PSAI;
Golombok & Rust, 1993a, 1993b) at three time points, when the child was 2.50, 3.50, and
4.75 years of age. The PSAI is standardized for use with children two to six years of age
(Golombok & Rust, 1993b), and it shows a large sex difference in children as young as two
years old (Golombok et al., 2008; Golombok & Rust, 1993a, 1993b; Wong & Hines, 2015). It
consists of 12 female-typical and 12 male-typical items measuring children’s preferences for
toys (7 items; e.g., tea set [female-typical]), activities (11 items; e.g., playing house [female-
typical]), and characteristics (6 items; e.g., enjoys rough-and-tumble play [male-typical]).
Caregivers rate the child’s behavior in the past month on a 5-point Likert scale,
ranging from 1 = never to 5 = very often. The total score for female-typical items is
subtracted from the total score for male-typical items to form a composite score. These
composite scores are then standardized using the same equation for girls and boys, with a
standardization target of M = 40 and SD = 10 for girls and M = 60 and SD = 10 for boys
(Golombok & Rust, 1993a, 1993b). This standardizing procedure aims to map childhood
gender-typed behavior on a pseudo-T scale with M = 50 and SD = 10 (Golombok & Rust,
1993a). Thus, larger standardized scores indicate more male-typical behavior and/or less
female-typical behavior for both girls and boys. The PSAI demonstrated good internal
consistency in the current sample, αs = .82, .88, and .91, in the 2.50-, 3.50-, and 4.75-year
data collections, respectively. Pearson’s correlations between PSAI scores at 2.50 years and
3.50 years, 2.50 years and 4.75 years, and 3.50 years and 4.75 years were .64, .53, and .70 for

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 12
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girls, respectively, and .64, .53, and .68 for boys, respectively, all ps < .001, demonstrating
high stability for gender-typed behavior across these years. These correlations are similar to
those reported previously for children in the ALSPAC sample across a similar age range
(Golombok et al., 2008).
Adolescent sexual orientation. At age 15 years, adolescents reported their sexual
orientation privately, on a computer, a procedure that can enhance self-disclosure of personal
information (Turner et al., 1998). As in Austin et al. (2009), Remafedi, Resnick, Blum, and
Harris (1992), and Saewyc, Skay, Bearinger, Blum, and Resnick, (1998), participants were
asked to report their sexual orientation on a 5-point scale similar to the Kinsey scale (Kinsey,
Pomeroy, & Martin, 1948): 1 = 100% heterosexual, 2 = mostly heterosexual but also
attracted to the same sex, 3 = bisexual (equally attracted to both sexes), 4 = mostly
lesbian/gay but also attracted to the other sex, 5 = 100% lesbian/gay, 6 = not sexually
attracted to either sex, 7 = not sure. Participants who selected 6 (n = 13) or 7 (n = 69) were
removed from analyses involving sexual orientation, because (a) there are no clear
predictions regarding differences in childhood gender-typed behavior between adolescents
with an asexual or questioning orientation and those with a heterosexual orientation and (b)
the majority of asexual and unsure adolescents are likely to self-identify as heterosexual in
late adolescence or adulthood (Ott, Corliss, Wypij, Rosario, & Austin, 2011; Savin-Williams
& Joyner, 2014a), so that it does not allow reliable comparisons of asexual or unsure
adolescents to heterosexual adolescents. This 5-point measure of sexual orientation has
shown similarly good stability (i.e., test-retest reliability) in adolescents and in young adults
(Ott et al., 2011), expected associations with the sex of sexual partners among adolescents
(Saewyc et al., 1998), and relatively low nonresponse rate among adolescents compared to
sexual orientation defined on other components (e.g., sexual fantasy; Saewyc et al., 2004).

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 13
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Thus, age 15 years appears to be a good age to start assessing self-reported sexual orientation
in a longitudinal study.
Considering recent debates about the reliability of measuring adolescent sexual
orientation (Katz-Wise, Calzo, Li, & Pollitt, 2015; Li, Katz-Wise, & Calzo, 2014; Savin-
Williams & Joyner, 2014a, 2014b), data on sexual behavior were also analyzed as a
reliability check. Sexual behavior was assessed using the Adolescent Sexual Activities Index
(ASAI; Hansen, Paskett, & Carter, 1999). Fourteen sexual activities were presented in the
order from low (e.g., “hugging”) to high (e.g., “having sexual intercourse”) intensity (Tables
5 & 6). Adolescents reported whether or not they had had each of the experiences in the past
year. Two stopping rules were used: If participants (1) answered “no” or skipped inquiries
about “cuddling,” “laying down together,” or “being undressed with private parts showing,”
or (2) skipped inquiries about “touching or fondling another young person’s private parts” or
“private parts being touched or fondled,” they did not progress to the rest of the questions.
The ASAI showed good internal consistency in this study, α = .93.
In addition to occurrence, adolescents reported the sex(es) of the person(s) with whom
they engaged in each sexual activity. For the purpose of the current study, adolescents who
reported exclusive other-sex contacts in a given sexual activity received a score of 0 on that
activity, and those who reported any same-sex contacts (including same-sex and both-sex
contacts) in a given sexual activity received a score of 1 on that activity. Comparisons were
not made between adolescents who had any same-sex (or other-sex) sexual contacts and those
who had no sexual contacts, because these two groups may not reflect differences in sexual
orientation, but may rather reflect differences in other factors such as the availability of
sexual partners. Also, because few adolescents had exclusive same-sex sexual contacts, they
were not distinguished from those with both-sex sexual contacts in the comparisons of
childhood gender-typed behavior.

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 14
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Missing Data
At the scale level, the four key variables had 2–8% missingness due to item
nonresponse (Table 1). These missing data were handled by full information maximum
likelihood in Mplus 7 (Muthén & Muthén, 1998–2015) in the latent growth modeling and by
multiple imputation in Amelia II 1.7.3 (Honaker, King, & Blackwell, 2012) followed by
Zelig 4.2-1 (Choirat, Honaker, Imai, King, & Lau, 2015) to pool the imputed data in the
ordinary least squares regression.
Results
Were There Differences in the Levels of Childhood Gender-Typed Behavior Between
Lesbian/Gay and Heterosexual Adolescents?
Sample size, mean, standard deviation, and range of each study variable are reported
in Table 1. To fully use the longitudinal assessments of childhood gender-typed behavior,
latent growth modeling was performed (Little, 2013). Latent intercept was separated from
latent slope, with the former estimating the mean level of childhood gender-typed behavior at
a chosen time point, and the latter estimating the rate of within-individual change from the
first to the last assessment. Previous research has found that children who were gender
nonconforming at age 3.50 years became increasingly so later in childhood (Golombok et al.,
2008); consequently, lesbian/gay individuals may exhibit more gender nonconforming
behavior than heterosexual counterparts, because they were gender nonconforming to start
with, or because they became more gender nonconforming over time. Distinguishing latent
intercept from latent slope allowed the investigation of relations between these individual
differences in the development of gender-typed behavior and adolescent sexual orientation.
Latent growth models were fitted separately by sex, with the standardized PSAI
scores at ages 2.50, 3.50, and 4.75 years used as indicators. Factor loadings on the latent
intercept were all fixed at 1; those on the latent slope were fixed by the time intervals in years

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between assessments. The latent intercept was alternately set to the three ages, so that the
mean level of gender-typed behavior was estimated for each age (Biesanz, Deeb-Sossa,
Papadakis, Bollen, & Curran, 2004). All other parameters were freely estimated. Table 2
shows that latent growth models fit well with the developmental trajectories of preschool
gender-typed behavior in girls and boys. All estimates presented in Table 2 were significantly
different from 0 at p < .001, two-tailed. The estimates of latent intercepts and slope indicated
that from ages 2.50 to 4.75 years, girls and boys on average increasingly conformed to the
behavioral norm of their own gender. The reproduced values of latent intercepts and slope for
each child were then predicted by adolescent sexual orientation and sexual activities in
ordinary least squares regression. Using the same set of latent intercepts and slope, rather
than estimating them in individual conditioned latent growth models (i.e., controlling for
sexual orientation or sexual activities while estimating latent growth factors), ensures high
accuracy in the estimates of latent intercepts and slope, especially when the sample size is
small (e.g., comparing adolescents who had oral sex with any same-sex partners to those with
exclusively other-sex partners in Tables 5 & 6).
Ordinary least squares regression demonstrated differences in the levels of childhood
gender-typed behavior between lesbian/gay and heterosexual adolescents (Tables 3 & 4).
Bonferroni corrections were applied to control for the inflated family-wise error rate due to
multiple comparisons. Starting at age 3.50 years in girls and 2.50 years in boys, pre-
lesbian/gay children exhibited significantly higher levels of gender nonconforming behavior
than same-sex pre-heterosexual peers. By Cohen’s (1988) benchmarks, the differences were
large from 3.50 years of age, ds > 0.8 (Tables 3 & 4).
To illustrate the size of the difference, histograms of the levels of gender-typed
behavior at ages 2.50, 3.50, and 4.75 years were drawn as a function of the sexual orientation
group (lesbian/gay or heterosexual) at age 15, for girls and boys (Figure 1). According to the

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 16
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frequency distributions, 6%, 6%, and 19% of lesbian girls scored above 56.45 on the PSAI
(equating to the 95th percentile in the target standardized distribution with an M of 40 and an
SD of 10) at ages 2.50, 3.50, and 4.75 years (and thus appeared to be extremely gender
nonconforming), respectively, while only 0.8%, 0.5%, and 1% of heterosexual girls did so
respectively. Similarly, 0%, 4%, and 13% of gay boys scored below 43.55 on the PSAI
(equating to the 5th percentile in the target standardized distribution with an M of 60 and an
SD of 10) at ages 2.50, 3.50, and 4.75 years (and thus appeared to be extremely gender
nonconforming), respectively, while the corresponding percentages for heterosexual boys
were 0.4%, 0.2%, and 0.5%, respectively.
Parallel analyses revealed a significant group difference in the levels of childhood
gender-typed behavior, starting at age 2.50 years, by the sex(es) of partner(s) with whom
adolescents had sexual contacts (Tables 5 & 6). Overall, 15-year-old adolescents who
reported certain types of sexual contacts with any same-sex partners showed higher levels of
gender nonconformity than same-sex peers who reported corresponding sexual contacts with
other-sex partners only. The effect sizes of the differences varied, with ranges of ds of [0.01,
1.04] in girls (median d = 0.24) and [-1.54, 0.03] in boys (median d = -0.36). The most
consistently predicted sexual activities by the levels of childhood gender-typed behavior were
ones of an intermediate to high level of intensity, such as kissing and being kissed on the
mouth, laying down together, touching partners under clothes, touching or fondling partners’
private parts, private parts being touched or fondled, and having oral sex (Tables 5 & 6). A
larger number of significant differences were observed in boys than in girls (28 versus 18;
Tables 5 & 6). Moreover, the levels of gender-typed behavior at older ages seemed to relate
to adolescents’ sexual behavior more strongly than the levels of gender-typed behavior at age
2.50 years, especially in boys (Tables 6).

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 17
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Was There a Monotonic Relation Between the Levels of Childhood Gender-Typed
Behavior and the Sexual Orientation Spectrum?
From self-identified heterosexual to bisexual to lesbian/gay, adolescents demonstrated
a monotonic increase in the levels of gender nonconforming behavior at ages 3.50 and 4.75
years, although not at age 2.50 years, after Bonferroni corrections (Tables 3 & 4). Further
division of sexual orientation into five categories saw similar monotonic associations with the
levels of gender-typed behavior at older ages, after Bonferroni corrections (Tables 3 & 4).
These associations were all linear (Tables 3 & 4).
What Was the Relation Between Change in Childhood Gender-Typed Behavior Over
Time and Adolescent Sexual Orientation?
Ordinary least squares regression demonstrated that change in gender-typed behavior
during preschool years also related significantly to adolescent sexual orientation. Specifically,
heterosexual adolescents increasingly conformed to their own gender norms from ages 2.50
to 4.75 years, whereas nonheterosexual adolescents became gender conforming at a slower
rate than heterosexual counterparts or became more gender nonconforming over the
preschool years (Tables 3 & 4). The significant differences in the latent slope between
heterosexual and lesbian/gay adolescents approximated a large size in girls (d = 0.72) and in
boys (d = -1.09). When sexual orientation was coded as a spectrum (either as three or five
groups) from heterosexual to lesbian/gay, the latent slope linearly increased in girls and
linearly decreased in boys, suggesting that compared to heterosexual adolescents, bisexuals
became gender conforming at a lower rate, and lesbian/gay individuals became gender
conforming at an even lower rate, or became more gender nonconforming before age 5 years.
After controlling for average levels of gender-typed behavior, change in gender-typed
behavior continued to significantly predict adolescent sexual orientation in boys in the same

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 18
!
manner as before, but did not predict adolescent sexual orientation in girls, regardless of how
adolescent sexual orientation was coded (Table S3).
Results for sexual activities suggested a similar picture: Adolescent girls who had
same-sex sexual contacts rarely differed significantly in change in childhood gender-typed
behavior during preschool years from girls who had exclusively other-sex sexual contacts
(Table 5). In contrast, adolescent boys who had same-sex contacts in some activities became
gender conforming at a lower rate or became more gender nonconforming during preschool
years than boys who had exclusively other-sex contacts in those activities (Table 6).
Discussion
This study examined the association between childhood gender-typed behavior and
adolescent sexual orientation, in a large sample from a longitudinal, population-based study.
The findings suggest that self-identified lesbian/gay adolescents are more likely than
heterosexual counterparts to have shown high levels of gender nonconforming behavior in
childhood. This significant and large group difference was seen before age 5 years.
Compared to heterosexual adolescent girls, lesbian girls were 12–19 times as likely to display
extreme levels of gender nonconforming behavior at ages 3.50 and 4.75 years; compared to
heterosexual adolescent boys, gay boys were 20–26 times as likely to display extreme levels
of gender nonconforming behavior at ages 3.50 and 4.75 years. Similarly, adolescents who
reported any same-sex sexual contacts (especially activities of an intermediate to high level
of intensity) also reported significantly higher levels of gender nonconforming behavior,
starting at age 2.50 years but more strongly and consistently at older ages (especially in boys),
than adolescents who had exclusively other-sex sexual contacts. In addition, the levels of
childhood behavioral gender nonconformity increased monotonically across the sexual
orientation spectrum from exclusively heterosexual to exclusively lesbian/gay, for both girls
and boys. Finally, we explored whether change in gender-typed behavior across the pre-

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 19
!
school years related significantly to adolescent sexual orientation, and to sexual activities,
and we found this to be the case, particularly in boys.
The findings in this study converge with those of previous studies to support a
difference in the levels of childhood gender nonconformity between groups of self-identified
lesbian/gay and heterosexual individuals. Further, the size of this group difference is
uniformly large: In retrospective studies, Cohen’s ds of 1.0 or larger have been observed (e.g.,
Bailey & Zucker, 1995; Rieger et al., 2008), exceeding the value of 0.8 that is considered to
be a large effect (Cohen, 1988). While retrospective studies are criticized as subject to self-
recall bias, the only existing longitudinal study also reported a large group difference (odds
ratios equaled 6.6 for women and 13.7 for men, corresponding to ds of 1.0 and 1.4; see Card,
2010, p. 119, for the equation that converts odds ratio to d; Steensma et al., 2013). Our d
values of 0.9 for girls and 1.2 for boys in a longitudinal, population-based sample, when
gender-typed behavior was measured at age 4.75 years, are similar to Steensma et al.’s
findings. The prospective design of the current study and of Steensma et al.’s suggests that
the connection is not merely a product of self-recall bias due to lesbian and gay people’s
internalized societal stereotypes (Ross, 1980; Gottschalk, 2003). It should also be noted that,
among potential childhood behavioral predictors of sexual orientation (e.g., familial factors
such as the parent-child relationship), gender-typed behavior appears to be the strongest one,
especially when predicting dichotomous differences between heterosexual and lesbian/gay
individuals (e.g., Bell, Weinberg, & Hammersmith, 1981; also reviewed in Bailey et al.,
2016).
Comparisons between two sexual activity groups yielded, with occasional exceptions,
smaller magnitudes of differences in childhood gender-typed behavior than comparisons
between two sexual orientation groups, according to Cohen’s ds (Tables 4 & 5). This may
have occurred because adolescent sexual activity is not a perfect indicator of adolescent

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 20
!
sexual orientation. For example, some self-identified nonheterosexual adults recall having
other-sex sexual contacts during adolescence (Herdt & Boxer, 1996; Rosario et al., 1996;
Savin-Williams, 1998), and some self-identified heterosexual adults recall having same-sex
sexual contacts during adolescence (Knight & Hope, 2012; Morgan, 2012; Morgan &
Thompson, 2011).
The present findings may have implications for understanding the factors that
influence individual variability in sexual orientation. We found that the differences in levels
of gender-typed behavior among sexual orientation groups emerged early, at as young as 2.50
to 3.50 years. This finding resembles the results of Rieger et al.’s (2008) study, which
reported that lesbian/gay individuals were more gender nonconforming than heterosexual
individuals starting from around age 3 years. In the current study, however, this difference
was statistically nonsignificant or smaller at age 2.50 years than it was at age 3.50 or 4.75
years. This smaller effect at age 2.50 years may reflect reduced sensitivity of the measure of
gender-typed play at the youngest age, given that sex differences in childhood gender-typed
play become more pronounced (and thus more observable) across childhood (Hines, 2015;
Wong & Hines, 2015). Nevertheless, the early emerging differences in gender-typed behavior
among sexual orientation groups suggest that any common factors affecting both traits are
likely to be present early in development.
The current study found that not only levels of gender nonconformity, but also change
in gender-typed behavior across the preschool years related significantly to later sexual
orientation, especially in boys. When heterosexual individuals, who comprised the majority
of participants, increasingly conformed to respective gender norms, nonheterosexual
individuals appeared to conform less, or became more nonconforming, over time. The link
between change in gender-typed behavior over time and adolescent sexual orientation is
unlikely to be caused by social factors, because there is widespread social encouragement to

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 21
!
conform to gender roles (Eagly, Wood, & Diekman, 2000; Eccles, Jacobs, & Harold, 1990),
and childhood gender nonconforming behavior can be associated with victimization
experiences (Katz-Wise & Hyde, 2012; Roberts, Rosario, Slopen, Calzo, & Austin, 2013),
which should discourage pre-nonheterosexual children from diverging from gender norms.
Nevertheless, how developmental change in childhood gender-typed behavior relates to later
sexual orientation merits further investigation, because evidence from this study is less
supportive of such a link in girls than in boys, and because we only assessed gender-typed
behavior across a short period of time.
Finally, the current study found that childhood gender nonconformity was
monotonically associated with same-sex sexual orientation within each sex. This finding is
consistent with predictions based on evidence that gendered traits may be correlated because
they share a common, monotonic influence of early androgen exposure (Hines, 2011). For
example, the extent to which a female with CAH prefers male-typical over female-typical
childhood activities, and female over male sexual partners both appear to be monotonically
influenced by the degree of prenatal androgen exposure due to CAH (Frisén et al., 2009;
Meyer-Bahlburg, Dolezal, Baker, & New, 2008). Similarly, in typically-developing girls and
boys, there is evidence that childhood gender-typed behavior is monotonically related to early
androgen concentrations (Hines et al., 2002; Lamminmäki et al., 2012; Pasterski et al., 2015),
although little is known about the relationship between early androgen levels and sexual
orientation in typically-developing individuals.
Results of the current study should be interpreted with some limitations in mind. First,
while the majority of prior studies relating childhood gender nonconformity to later sexual
orientation measured sexual orientation in adulthood (with the exception of Rieger & Savin-
Williams, 2012), the current study measured sexual orientation in adolescence. Because the
number of people who identify as nonheterosexual, especially as lesbian/gay, increases from

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 22
!
adolescence to adulthood (Austin et al., 2009; Remafedi et al., 1992), it is possible that
assessments of our cohort at later ages would produce somewhat different results. In addition,
because our study focused on adolescents, some of our participants were at earlier pubertal
stages than others. Nevertheless, in the current study the significance levels for the relations
between childhood gender-typed behavior and adolescent sexual orientation remained largely
unchanged after controlling for pubertal development statuses (Tables S4 & S5). Second,
ongoing debates question whether adolescents accurately report their sexual orientation
(Katz-Wise et al., 2015; Li et al., 2014; Savin-Williams & Joyner, 2014a, 2014b). Although
our measurement of sexual orientation at age 15 years appeared to be sufficiently reliable to
detect similar relations to childhood gender nonconformity to those seen in prior studies,
future research might usefully study this cohort at older ages. Future studies also might
usefully explore the connection between childhood gender-typed behavior and sexual
orientation measured using methods other than self-reports, such as pupil dilation and genital
arousal (e.g., Rieger, Savin-Williams, Chivers, & Bailey, 2015).
Conclusion
By age 2.50 to 3.50 years, children’s gender-typed behavior significantly predicts
future sexual orientation. Children who exhibit more gender nonconformity in regard to toys,
playmates, and activities are more likely to later report more same-sex and/or less other-sex
sexual attraction and behavior. The current results converge with other lines of retrospective
and prospective research to suggest that childhood gender nonconforming behavior is a
consistent early predictor of future nonheterosexual orientations. This observed relation may
be partly driven by other factors, such as early androgen exposure or common genes, that
affect behavior early in development.

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 23
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Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 36
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Table 1
Descriptive Statistics of Key Variables by Sex
Girls
Boys
n
M
SD
Range
n
M
SD
Range
Sexual orientation at age 15 yearsa
2,428
1.17
0.48
1–5
2,169
1.13
0.48
1–5
Gender-typed behavior at age 2.50 yearsb
2,241
40.99
8.46
8.65–71.35
2,010
59.87
8.24
27.35–92.25
Gender-typed behavior at age 3.50 yearsb
2,360
37.08
9.31
4.25–72.45
2,125
61.54
8.69
20.75–95.55
Gender-typed behavior at age 4.75 yearsb
2,228
35.28
9.51
4.25–90.05
2,026
63.42
8.78
16.35–93.55
a1 = 100% heterosexual; 5 = 100% lesbian/gay.
bLarger scores represent higher levels of male-typical behavior and/or lower levels of female-typical behavior.

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 37
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Table 2
Latent Linear Growth Models of Childhood Gender-Typed Behavior by Sex With Intercepts Fixed at Different Ages
Intercept
Slope
Intercept-slope
Intercept fixed at
Mean
Variance
Mean
Variance
Covariance
Girls
Model fit: c2(1) = 113.63, p < .001; CFI = .956; TLI = .867; RMSEA [90% CI] = .22 [.18, .25]
2.50 years
40.55 (0.18)
55.19 (2.61)
-2.42 (0.09)
11.53 (1.02)
-5.93 (1.12)
3.50 years
38.12 (0.16)
54.86 (1.91)
-2.42 (0.09)
11.54 (1.02)
5.60 (0.81)
4.75 years
35.09 (0.20)
86.89 (3.89)
-2.42 (0.09)
11.54 (1.02)
20.02 (1.70)
Boys
Model fit: c2(1) = 0.90, p = .342; CFI > .999; TLI > .999; RMSEA [90% CI] = .00 [.00, .06]
2.50 years
59.83 (0.18)
52.39 (8.78)
1.61 (0.08)
8.78 (0.93)
-6.31 (1.07)
3.50 years
61.43 (0.16)
48.55 (1.77)
1.61 (0.08)
8.78 (0.93)
2.47 (0.73)
4.75 years
63.44 (0.19)
68.45 (3.34)
1.61 (0.08)
8.78 (0.93)
13.45 (1.47)
Note. Each row represents an individual latent growth model, but the model fit remained the same within each sex regardless how the intercept
was fixed. All estimates in this table were significantly different from 0 at p < .001, two-tailed. Values outside and inside the parentheses
represent unstandardized estimates and standard errors. CFI = comparative fit index. TLI = Tucker–Lewis index. RMSEA = root mean square
error of approximation. CI = confidence interval.

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 38
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Table 3
Latent Growth Factors of Gender-Typed Behavior During Preschool Years by Sexual Orientation at Age 15 Years in Girls
Sexual orientation
n
Intercept at age 2.50
yearsa
Intercept at age 3.50
yearsa
Intercept at age 4.75
yearsa
Slopeb
M
SD
M
SD
M
SD
M
SD
2-groupc
Heterosexuald
2,366
40.47
6.55
38.03
6.96
34.99
8.82
-2.44
2.81
Lesbiane
16
44.11
8.03
43.70
8.87
43.18
11.69
-0.41
3.78
df
0.56
0.81
0.93
0.72
3-groupg
Heterosexuald
2,366
40.47
6.55
38.03
6.96
34.99
8.82
-2.44
2.81
Bisexual
46
43.34
7.07
40.90
8.51
37.84
11.32
-2.45
3.14
Lesbiane
16
44.11
8.03
43.70
8.87
43.18
11.69
-0.41
3.78
5-grouph
100% heterosexual
2,094
40.27
6.56
37.83
6.95
34.78
8.78
-2.44
2.80
Mostly heterosexual
272
42.04
6.24
39.61
6.84
36.57
8.95
-2.43
2.90
Bisexual
46
43.34
7.07
40.90
8.51
37.84
11.32
-2.45
3.14
Mostly lesbian
12
42.68
8.22
41.30
7.48
39.58
8.59
-1.37
3.40
100% lesbian
4
48.42
6.43
50.89
9.81
53.97
14.34
2.47
3.79
aLarger scores represent higher levels of male-typical behavior and/or lower levels of female-typical behavior.
bAbove zero: larger scores represent a larger increase in male-typical behavior and/or a larger decrease in female-typical behavior; below zero:
smaller scores represent a larger increase in female-typical behavior and/or a larger decrease in male-typical behavior.
cLinear regression with Bonferroni correction (α = .05/4 = .013, two-tailed) indicated a significant difference between heterosexual and lesbian
girls in the intercepts of gender-typed behavior at age 3.50 years, B = 5.66, SE = 1.75, p < .001, and at age 4.75 years, B = 8.19, SE = 2.22, p
< .001, and in the slope of gender-typed behavior during preschool years, B = 2.02, SE = 0.71, p = .004.
dComprising 100% heterosexual and mostly heterosexual.
eComprising mostly lesbian and 100% lesbian.
fCohen’s d was pooled following Rubin’s (1987) rule. Similarly to Bailey and Zucker (1995), Hedges’s (1982; Formula 4) unbiasing correction
was applied.
gOrthogonal polynomial contrasts with Bonferroni correction (α = .05/8 = .006, two-tailed) indicated a significant linear effect of sexual
orientation groups in girls on the intercepts of gender-typed behavior at age 3.50 years, B = 4.01, SE = 1.24, p < .001, and at age 4.75 years, B =

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 39
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5.79, SE = 1.58, p < .001, and on the slope of gender-typed behavior during preschool years, B = 1.43, SE = 0.50, p = .004. No other significant
linear effects or any quadratic effects were detected, ps > .027 (see Table S1 for more information).
hOrthogonal polynomial contrasts with Bonferroni correction (α = .05/16 = .003, two-tailed) indicated a significant linear effect of sexual
orientation groups in girls on the intercepts of gender-typed behavior at age 3.50 years, B = 8.79, SE = 2.30, p = .001, and at age 4.75 years, B =
13.08, SE = 2.92, p < .001, and on the slope of gender-typed behavior during preschool years, B = 3.44, SE = 0.93, p < .001. No other significant
linear effects or any quadratic, cubic, or quartic effects were detected, ps > .004 (see Table S1 for more information).

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 40
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Table 4
Latent Growth Factors of Gender-Typed Behavior During Preschool Years by Sexual Orientation at Age 15 Years in Boys
Sexual orientation
n
Intercept at age 2.50
yearsa
Intercept at age 3.50
yearsa
Intercept at age 4.75
yearsa
Slopeb
M
SD
M
SD
M
SD
M
SD
2-groupc
Heterosexuald
2,117
59.90
6.42
61.56
6.47
63.63
7.53
1.66
2.24
Gaye
24
56.45
6.05
55.66
6.82
54.67
9.21
-0.79
3.04
df
-0.54
-0.91
-1.19
-1.09
3-groupg
Heterosexuald
2,117
59.90
6.42
61.56
6.47
63.63
7.53
1.66
2.24
Bisexual
28
57.34
8.70
57.12
9.32
56.84
11.56
-0.22
3.40
Gaye
24
56.45
6.05
55.66
6.82
54.67
9.21
-0.79
3.04
5-grouph
100% heterosexual
1,981
60.01
6.41
61.69
6.47
63.79
7.53
1.68
2.22
Mostly heterosexual
136
58.32
6.37
59.64
6.12
61.28
7.16
1.31
2.51
Bisexual
28
57.34
8.70
57.12
9.32
56.84
11.56
-0.22
3.40
Mostly gay
13
55.99
5.90
55.35
6.85
54.54
9.79
-0.65
3.47
100% gay
11
56.99
6.47
56.03
7.10
54.83
8.95
-0.96
2.60
aLarger scores represent higher levels of male-typical behavior and/or lower levels of female-typical behavior.
bAbove zero: larger scores represent a larger increase in male-typical behavior and/or a larger decrease in female-typical behavior; below zero:
smaller scores represent a larger increase in female-typical behavior and/or a larger decrease in male-typical behavior.
cLinear regression with Bonferroni correction (α = .05/4 = .013, two-tailed) indicated a significant difference between heterosexual and gay boys
in the intercepts of gender-typed behavior at age 2.50 years, B = -3.45, SE = 1.32, p = .009, at age 3.50 years, B = -5.90, SE = 1.33, p < .001, and
at age 4.75 years, B = 8.96, SE = 1.55, p < .001, and in the slope of gender-typed behavior during preschool years, B = -2.45, SE = 0.46, p < .001.
dComprising 100% heterosexual and mostly heterosexual.
eComprising mostly gay and 100% gay.
fCohen’s d was pooled following Rubin’s (1987) rule. Similarly to Bailey and Zucker (1995), Hedges’s (1982; Formula 4) unbiasing correction
was applied.
gOrthogonal polynomial contrasts with Bonferroni correction (α = .05/8 = .006, two-tailed) indicated a significant linear effect of sexual
orientation groups in boys on the intercepts of gender-typed behavior at age 3.50 years, B = -4.17, SE = 0.95, p < .001, and at age 4.75 years, B =

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 41
!
-6.33, SE = 1.11, p < .001, and on the slope of gender-typed behavior during preschool years, B = -1.73, SE = 0.33, p < .001. No other significant
linear effects or any quadratic effects were detected, ps > .009 (see Table S1 for more information).
hOrthogonal polynomial contrasts with Bonferroni correction (α = .05/16 = .003, two-tailed) indicated a significant linear effect of sexual
orientation groups in boys on the intercepts of gender-typed behavior at age 3.50 years, B = -4.94, SE = 1.38, p < .001, and at age 4.75 years, B =
-7.80, SE = 1.61, p < .001, and on the slope of gender-typed behavior during preschool years, B = -2.29, SE = 0.48, p < .001. No other significant
linear effects or any quadratic, cubic, or quartic effects were detected, ps > .053 (see Table S1 for more information).

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 42
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Table 5
Latent Growth Factors of Gender-Typed Behavior During Preschool Years by Sexual Activities at Age 15 Years in Girls Who Had Sexual
Contacts
Sexual activity
n
Intercept at age 2.50
yearsa
Intercept at age 3.50
yearsa
Intercept at age 4.75
yearsa
Slopeb
M
SD
M
SD
M
SD
M
SD
Hug
Exclusive other-sex contacts
173
40.26
6.95
37.74
6.89
34.58
8.16
-2.52
2.68
Any same-sex contacts
2,231
40.55
6.55
38.13
7.04
35.10
8.98
-2.42
2.85
d
0.04
0.06
0.06
0.04
Hold hands
Exclusive other-sex contacts
864
40.39
6.54
37.75
6.86
34.45
8.58
-2.64c
2.73
Any same-sex contacts
1,209
40.47
6.55
38.19
7.02
35.33
9.00
-2.28
2.90
d
0.01
0.06
0.09
0.13
Spend time alone
Exclusive other-sex contacts
476
40.13
6.63
37.55
6.99
34.33
8.76
-2.58
2.79
Any same-sex contacts
1,775
40.56
6.56
38.17
6.99
35.18
8.87
-2.39
2.82
d
0.07
0.09
0.10
0.06
Kiss on the mouth
Exclusive other-sex contacts
1,483
40.15c
6.55
37.70c
6.87
34.64c
8.63
-2.45
2.79
Any same-sex contacts
366
41.80
6.72
39.55
7.43
36.74
9.68
-2.25
3.02
d
0.25
0.27
0.24
0.07
Be kissed on the mouth
Exclusive other-sex contacts
1,486
40.34c
6.57
37.93c
6.95
34.92c
8.77
-2.41
2.81
Any same-sex contacts
266
41.49
6.78
39.31
7.32
36.59
9.40
-2.17
3.00
d
0.17
0.20
0.19
0.08
Cuddle
Exclusive other-sex contacts
1,363
40.35
6.58
37.85
6.95
34.73
8.79
-2.50
2.84
Any same-sex contacts
565
40.76
6.40
38.44
7.06
35.54
9.20
-2.32
2.90
d
0.06
0.08
0.09
0.06
Lay down together

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 43
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Exclusive other-sex contacts
1,159
40.23c
6.58
37.83c
6.89
34.83
8.63
-2.40
2.77
Any same-sex contacts
365
41.32
6.28
38.89
6.83
35.85
8.83
-2.43
2.82
d
0.17
0.15
0.12
-0.01
Be touched under clothes
Exclusive other-sex contacts
1,191
40.50
6.55
38.06
6.87
35.01
8.61
-2.44
2.77
Any same-sex contacts
50
42.07
8.05
39.82
9.15
37.00
11.89
-2.25
3.48
d
0.24
0.25
0.23
0.07
Touch under clothes
Exclusive other-sex contacts
1,018
40.46
6.61
38.02c
6.88
34.97c
8.54
-2.44
2.73
Any same-sex contacts
49
42.51
8.03
41.03
9.26
39.18
12.25
-1.48
3.66
d
0.31
0.43
0.48
0.35
Be undressed with private parts
showing
Exclusive other-sex contacts
742
40.47c
6.56
38.02
6.87
34.96
8.56
-2.45
2.73
Any same-sex contacts
59
42.99
6.58
39.98
7.85
36.22
10.72
-3.01
3.28
d
0.39
0.28
0.14
-0.20
Touch or fondle private parts
Exclusive other-sex contacts
700
40.54c
6.62
38.09c
6.94
35.02
8.66
-2.46
2.77
Any same-sex contacts
26
44.06
7.15
41.93
9.07
39.25
12.47
-2.14
3.50
d
0.53
0.55
0.48
0.11
Private parts be touched or
fondled
Exclusive other-sex contacts
710
40.53c
6.54
38.04c
6.85
34.93
8.58
-2.49
2.76
Any same-sex contacts
25
44.93
7.44
42.41
9.05
39.25
12.14
-2.52
3.38
d
0.67
0.63
0.50
-0.01
Have oral sex
Exclusive other-sex contacts
570
40.65c
6.48
38.10c
6.78
34.91c
8.55
-2.55
2.80
Any same-sex contacts
11
47.40
8.70
45.18
11.80
42.40
16.49
-2.23
4.34
d
1.04
1.03
0.86
0.11
Have sexual intercourse
Exclusive other-sex contacts
483
40.56
6.57
38.06
6.79
34.93
8.43
-2.50
2.75
Any same-sex contacts
6
43.39
8.90
40.73
8.70
37.40
8.48
-2.66
0.45

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 44
!
d
0.43
0.39
0.29
-0.07
Note. Girls who did not engage in a given sexual activity or did not indicate the sex(es) of the partner(s) were excluded from the analysis.
Cohen’s d was pooled following Rubin’s (1987) rule. Similarly to Bailey and Zucker (1995), Hedges’s (1982; Formula 4) unbiasing correction
was applied.
aLarger scores represent higher levels of male-typical behavior and/or lower levels of female-typical behavior.
bAbove zero: larger scores represent a larger increase in male-typical behavior and/or a larger decrease in female-typical behavior; below zero:
smaller scores represent a larger increase in female-typical behavior and/or a larger decrease in male-typical behavior.
cValue significantly differs from that in the row immediately below, after Bonferroni correction (α = .05/4 = .013, two-tailed). See Table S2 for
more information.

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 45
!
Table 6
Latent Growth Factors of Gender-Typed Behavior During Preschool Years by Sexual Activities at Age 15 Years in Boys Who Had Sexual
Contacts
Sexual activity
n
Intercept at age 2.50
yearsa
Intercept at age 3.50
yearsa
Intercept at age 4.75
yearsa
Slopeb
M
SD
M
SD
M
SD
M
SD
Hug
Exclusive other-sex contacts
1,121
59.85
6.67
61.45
6.77
63.45
7.89
1.60
2.29
Any same-sex contacts
949
59.85
6.27
61.51
6.37
63.60
7.57
1.66
2.32
d
0.00
0.01
0.02
0.03
Hold hands
Exclusive other-sex contacts
1,531
60.10
6.54
61.74
6.59
63.78
7.67
1.64
2.27
Any same-sex contacts
161
59.36
6.42
60.79
6.83
62.57
8.51
1.43
2.60
d
-0.11
-0.14
-0.16
-0.09
Spend time alone
Exclusive other-sex contacts
920
60.40c
6.67
62.00c
6.77
64.00c
7.79
1.60
2.17
Any same-sex contacts
927
59.41
6.34
61.02
6.48
63.02
7.76
1.60
2.39
d
-0.15
-0.15
-0.13
0.00
Kiss on the mouth
Exclusive other-sex contacts
1,448
60.29c
6.50
61.95c
6.53
64.01c
7.58
1.65
2.24
Any same-sex contacts
69
58.21
5.81
59.35
6.32
60.78
8.62
1.14
3.07
d
-0.32
-0.40
-0.42
-0.22
Be kissed on the mouth
Exclusive other-sex contacts
1,361
60.37c
6.46
62.02c
6.50
64.07c
7.53
1.64
2.22
Any same-sex contacts
65
58.62
5.95
59.77
6.76
61.22
9.35
1.16
3.21
d
-0.27
-0.34
-0.37
-0.21
Cuddle
Exclusive other-sex contacts
1,466
60.11
6.49
61.72
6.58
63.73c
7.69
1.61
2.27
Any same-sex contacts
104
59.18
6.26
60.23
6.65
61.55
8.67
1.06
2.96
d
-0.14
-0.22
-0.28
-0.24
Lay down together

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 46
!
Exclusive other-sex contacts
1,048
60.55
6.54
62.17c
6.54
64.20c
7.48
1.62
2.17
Any same-sex contacts
82
58.95
6.30
60.11
7.14
61.56
9.60
1.16
3.10
d
-0.24
-0.31
-0.34
-0.21
Be touched under clothes
Exclusive other-sex contacts
843
60.69c
6.61
62.35c
6.65
64.42c
7.60
1.65c
2.14
Any same-sex contacts
34
57.40
4.74
57.74
5.47
58.16
8.79
0.33
3.67
d
-0.50
-0.70
-0.82
-0.60
Touch under clothes
Exclusive other-sex contacts
849
60.58c
6.59
62.24c
6.61
64.33c
7.54
1.67c
2.13
Any same-sex contacts
34
57.41
4.59
57.73
5.76
58.14
9.51
0.32
3.87
d
-0.49
-0.69
-0.81
-0.61
Be undressed with private parts
showing
Exclusive other-sex contacts
544
60.84
6.76
62.52
6.80
64.62c
7.75
1.68c
2.15
Any same-sex contacts
38
59.43
5.75
60.02
7.18
60.75
10.51
0.59
3.56
d
-0.21
-0.37
-0.49
-0.48
Touch or fondle private parts
Exclusive other-sex contacts
513
61.01c
6.78
62.73
6.89
64.87c
7.90
1.72c
2.16
Any same-sex contacts
26
57.41
4.88
56.79
5.39
56.01
8.49
-0.62
3.60
d
-0.54
-0.87
-1.12
-1.04
Private parts be touched or
fondled
Exclusive other-sex contacts
498
61.07
6.72
62.78c
6.81
64.91c
7.78
1.71c
2.13
Any same-sex contacts
26
59.11
6.64
57.91
7.23
56.42
9.94
-1.19
3.59
d
-0.29
-0.70
-1.05
-1.26
Have oral sex
Exclusive other-sex contacts
413
61.30c
6.75
62.94c
6.79
64.99c
7.70
1.64c
2.11
Any same-sex contacts
22
57.34
4.57
56.58
5.47
55.63
8.88
-0.76
3.66
d
-0.60
-0.95
-1.21
-1.09
Have sexual intercourse
Exclusive other-sex contacts
322
61.19
6.82
62.78c
6.93
64.76c
7.94
1.59c
2.17
Any same-sex contacts
8
60.07
4.66
58.17
7.14
55.81
12.33
-1.89
4.78

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 47
!
d
-0.17
-0.66
-1.11
-1.54
Note. Boys who did not engage in a given sexual activity or did not indicate the sex(es) of the partner(s) were excluded from the analysis.
Cohen’s d was pooled following Rubin’s (1987) rule. Similarly to Bailey and Zucker (1995), Hedges’s (1982; Formula 4) unbiasing correction
was applied.
aLarger scores represent higher levels of male-typical behavior and/or lower levels of female-typical behavior.
bAbove zero: larger scores represent a larger increase in male-typical behavior and/or a larger decrease in female-typical behavior; below zero:
smaller scores represent a larger increase in female-typical behavior and/or a larger decrease in male-typical behavior.
cValue significantly differs from that in the row immediately below, after Bonferroni correction (α = .05/4 = .013, two-tailed). See Table S2 for
more information.

Running head: GENDER-TYPED BEHAVIOR AND SEXUAL ORIENTATION 48
!
Figure 1. Frequency distributions of the levels of gender-typed behavior at preschool years by 2-group sexual orientation at age 15 years.
Within-group percentages are presented. Levels of gender-typed behavior were estimated using the Preschool Activity Inventory (PSAI;
Golombok & Rust, 1993a, 1993b). Larger PSAI intercepts indicate more male-typical behavior and/or less female-typical behavior.