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In species in which males care for young, testosterone (T) is often high during mating periods but then declines to allow for caregiving of resulting offspring. This model may apply to human males, but past human studies of T and fatherhood have been cross-sectional, making it unclear whether fatherhood suppresses T or if men with lower T are more likely to become fathers. Here, we use a large representative study in the Philippines (n = 624) to show that among single nonfathers at baseline (2005) (21.5 ± 0.3 y), men with high waking T were more likely to become partnered fathers by the time of follow-up 4.5 y later (P < 0.05). Men who became partnered fathers then experienced large declines in waking (median: -26%) and evening (median: -34%) T, which were significantly greater than declines in single nonfathers (P < 0.001). Consistent with the hypothesis that child interaction suppresses T, fathers reporting 3 h or more of daily childcare had lower T at follow-up compared with fathers not involved in care (P < 0.05). Using longitudinal data, these findings show that T and reproductive strategy have bidirectional relationships in human males, with high T predicting subsequent mating success but then declining rapidly after men become fathers. Our findings suggest that T mediates tradeoffs between mating and parenting in humans, as seen in other species in which fathers care for young. They also highlight one likely explanation for previously observed health disparities between partnered fathers and single men.
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Longitudinal evidence that fatherhood decreases
testosterone in human males
Lee T. Gettler
, Thomas W. McDade
, Alan B. Feranil
, and Christopher W. Kuzawa
Department of Anthropology, and
Cells to Society, Center on Social Disparities and Health, Institute for Policy Research, Northwestern University, Evanston,
IL 60208; and
Ofce of Population Studies Foundation, University of San Carlos, Cebu City 6000, Philippines
Edited by A. E. Storey, Department of Psychology, Memorial University of Newfoundland, St. Johns, NF, Canada, and accepted by the Editorial Board July 28,
2011 (received for review May 10, 2011)
In species in which males care for young, testosterone (T) is often
high during mating periods but then declines to allow for
caregiving of resulting offspring. This model may apply to human
males, but past human studies of T and fatherhood have been
cross-sectional, making it unclear whether fatherhood suppresses
T or if men with lower T are more likely to become fathers. Here,
we use a large representative study in the Philippines (n= 624) to
show that among single nonfathers at baseline (2005) (21.5 ±0.3 y),
men with high waking T were more likely to become partnered
fathers by the time of follow-up 4.5 y later (P<0.05). Men who
became partnered fathers then experienced large declines in wak-
ing (median: 26%) and evening (median: 34%) T, which were
signicantly greater than declines in single nonfathers (P<0.001).
Consistent with the hypothesis that child interaction suppresses T,
fathers reporting 3 h or more of daily childcare had lower T at
follow-up compared with fathers not involved in care (P<0.05).
Using longitudinal data, these ndings show that T and reproduc-
tive strategy have bidirectional relationships in human males, with
high T predicting subsequent mating success but then declining
rapidly after men become fathers. Our ndings suggest that T
mediates tradeoffs between mating and parenting in humans, as
seen in other species in which fathers care for young. They also
highlight one likely explanation for previously observed health
disparities between partnered fathers and single men.
challenge hypothesis
human evolution
hormones and behavior
paternal care
reproductive ecology
In male mammals, testosterone (T) stimulates the development
and maintenance of traits and behaviors that contribute to
male mating effort, including musculature, libido, conspecic
aggressivity, and courtship (14). Although these T-driven traits
factor into mating success, male reproductive tness in some
avian and mammalian species also depends on contributions to
offspring care (5, 6). Because time and energy are nite (7),
males in these species often face tradeoffs between conicting
behaviors related to mating and parenting. Adjustment of T
production has been proposed as a physiological mechanism
underlying this tradeoff, with males who focus on mating effort
predicted to maintain elevated T, whereas males who cooperate
with a female partner and invest in parental care should reduce T
production (6, 8). This model is well supported by data from
a variety of avian species (6, 8), but evidence for its applicability
to mammalian species in which males provide direct care is
mixed (9). It is presently unclear whether T mediates the tradeoff
between mating and parenting effort in human males, who often
express paternal care facultatively.
Humans have been described as serial monogamists who fre-
quently engage in one or more long-lasting partnerships with
females during reproductive life spans that last several decades
(1012). Humans are one of the few mammalian species in which
paternal care is relatively common, with fathers often helping to
raise multiple overlapping offspring who are dependent well into
their second decade of life (5, 1315). If T contributes to human
male reproductive strategy, high initial T should enhance a mans
mating success, but men who have succeeded in securing a mate
and/or fathering a child should then down-regulate T, particu-
larly if they frequently care for their children (6, 8, 13).
Past human work provides indirect support for these expect-
ations largely using cross-sectional data. Multiple studies have
shown that partnered men have lower T compared with single
men (16, 17), and a large 10-y study of US servicemen found that
T decreased in men who married during the study period (18). In
comparisons of men varying in both relationship and parenting
status, partnered fathers have been shown to have the lowest T
overall, differing signicantly from single nonfathers in some
populations (1921), including the present study population (22,
23). There is also increasing evidence that caregiving predicts
which fathers have lowest T (20, 22, 24). Although these cross-
sectional correlations are generally consistent with the presumed
suppressive effect of partnering and fatherhood on T production
(a stateeffect), such ndings could alternatively result if men
with low T are more likely to become partnered or fathers (a
traiteffect) (25). However, to date, no human study has
monitored hormonal changes longitudinally as single nonfathers
transition into stable partnerships and become fathers.
To clarify the role of T in human male reproductive strategy,
we draw on data and biological samples collected in a large
sample of men participating in the Cebu Longitudinal Health
and Nutrition Survey (CLHNS), a representative 1-y birth cohort
study begun in the Philippines in 1983. In addition to longitu-
dinal questionnaire data, we collected saliva samples for T
measurement at waking (AM) and before bed (PM) in all par-
ticipants (n= 624) when they were 21.5 (±0.3) y of age (base-
line) and again when they were 26.0 (±0.3) y of age (follow-up).
All participants live in or around Cebu City, the Philippines,
where it is common for fathers to be involved in day-to-day care
of their children (22). Focusing on the subsample of men who
were single nonfathers at baseline (n= 465), we tested the hy-
potheses that (i) men with higher baseline T would have greater
mating success as indicated by being in a stable partnership
(married/cohabitating) and/or becoming a father by the time of
follow-up and (ii) these newly partnered new fathers would
subsequently show a greater decrease in T than men who
remained single nonfathers. We also tested the hypothesis that
(iii) fathers who reported spending more time in childcare would
have lower T at follow-up than fathers who reported spending
Author contributions: L.T.G., A.B.F., and C.W.K. designed research; L.T.G., T.W.M., A.B.F.,
and C.W.K. performed research; L.T.G. and C.W.K. analyzed data; and L.T.G., T.W.M.,
A.B.F., and C.W.K. wrote the paper.
The authors declare no conict of interest.
This article is a PNAS Direct Submission. A.E.S. is a guest editor invited by the Editorial
See Commentary on page 16141.
L.T.G. and C.W.K. contributed equally to this work.
To whom correspondence may be addressed. E-mail: or
This article contains supporting information online at
September 27, 2011
vol. 108
no. 39
less time in childcare, as would be consistent with a direct sup-
pressive role of caregiving on T among fathers.
In observational research, correlated nonmeasured factors can
inuence both predictor and outcome variables, and thus lead to
confounded associations. Here, we use an econometric change
model that minimizes the likelihood of such confounding, be-
cause any permanent or stable factors that differ among men but
that have not changed in the follow-up period are included
within the error term of both regression models, and thus are
eliminated as potential inuences on any change in T experi-
enced during the period of follow-up (26).
Table 1 summarizes sociodemographic and biological charac-
teristics for the full sample and also stratied on a median split of
AM T measured at follow-up (2009). When the full sample was
considered, all men showed a modest but signicant decrease in
both AM and PM T between baseline and follow-up, consistent
with age-related declines documented previously (27). Men with
high T tended to have completed more years of education,
whereas men with low and high T did not differ in anthropo-
metric measures. Consistent with the results presented below,
a greater proportion of partnered men and fathers had T below
the median.
We rst used logistic regression to test whether T at baseline
predicted reproductive status at follow-up (n= 465; Table S1).
Consistent with our hypothesis, single nonfathers with greater
AM T at baseline were more likely to become newly partnered
[odds ratio (OR) = 1.20, P= 0.044] and newly partnered new
fathers (OR = 1.21, P= 0.048) by the time of follow-up in 2009.
We next tested whether men who became newly partnered
new fathers during the period of follow-up experienced a greater
decline in T relative to men who remained single nonfathers
between baseline and follow-up. Consistent with this hypothesis,
men who were both newly partnered and new fathers showed the
largest declines in AM and PM T between 2005 and 2009 (Fig. 1
Aand B), and their declines in both AM (median: 26%) and
PM (median: 34%) T were signicantly greater than the
modest age-related declines in AM (median: 12%) and PM
(median: 14%) T observed among single nonfathers (P<0.001,
n= 465; Fig. 1Band Tables S2 and S3). Newly partnered men
who remained nonfathers at follow-up showed declines in AM
(median: 10%) and PM (median: 32%) T (Fig. 1A) that were
not signicantly different from those of single nonfathers [ab-
solute change in AM T (ΔAM T), P= 0.499; ΔPM T, P= 0.167;
Fig. 1Band Tables S2 and S3]. Effects of change in partnering
and fatherhood status on ΔAM and ΔPM T were not sub-
stantially affected after adjusting for self-reported psychosocial
stress and sleep quality, neither of which signicantly predicted
ΔT (all P>0.3; Tables S2 and S3). In addition, men who were
partnered fathers in 2005 and who already had low T at baseline
showed only slight within-group declines in both ΔAM T (me-
dian: 7%, P= 0.048; n= 83) and ΔPM T (median: 3%, P=
0.374) by follow-up in 2009 (Fig. 1Aand Table S4).
We next tested whether the large decrease in T among new
fathers was contingent on the age of a mans youngest child.
Although all new fathers, regardless of their youngest childs age,
experienced a signicant reduction in AM and/or PM T com-
pared with nonfathers (Fig. 2 and Tables S5 and S6), fathers with
newborns (1 mo old or less) at the time of follow-up hormone
assessment showed signicantly greater declines in AM (P=
0.023) and PM (P= 0.003) T compared with fathers whose
youngest child was older than 1 y of age, which was not ac-
counted for by reports of psychosocial stress, sleep quality, or
involvement in caregiving (Tables S7 and S8). Men with new-
borns also differed signicantly for ΔAM T compared with men
with infants between 1 mo and 1 y of age (P= 0.007).
Finally, we evaluated whether men who were fathers at follow-
up (n= 312) varied in T based on their self-reported in-
volvement in childcare in 2009, controlling for sleep quality,
psychosocial stress, and number of children. Men reporting 13h
of daily childcare had signicantly lower AM T compared with
fathers reporting not being involved with care (Fig. 3), whereas
fathers reporting the highest involvement in childcare (3 h or
more per day) showed signicantly lower values of both AM and
PM T compared with men reporting no care (Fig. 3). Consistent
with the hypothesis that childcare suppresses T, among men who
began as nonpartnered nonfathers at baseline (n= 162), time
Fig. 1. (A) Within-group changes in AM and PM T values between 2005 and 2009. Mean values of T, adjusted for time of saliva collection and usual wake
time (AM), were compared using paired ttests. Group 1 (n= 83) comprised men who were partnered and fathers in 2005 and 2009. Group 2 (n= 257)
comprised men who were not partnered in 2005 and 2009 and were never fathers. Group 3 (n= 46) comprised men who became partnered between 2005 and
2009 and were never fathers. Group 4 (n= 162) comprised men who became partnered and were rst-time fathers between 2005 and 2009. *P<0.05; **P<
P<0.0001. Error bars indicate SEM. P, partnered. (B) Between-group changes in AM and PM T values between 2005 and 2009 based on partnering and
parenting status. Group descriptions are as in A. Values were adjusted for time of saliva collection and usual wake time (AM) and are derived from regressing
the change in T on changes in partnering and parenting status, with group 2 as the comparison group, controlling for sleep quality and psychosocial stress
(Tables S2 and S3). Partnered fathers are included for visual comparison but were not part of the regression analyses. ***P<0.001. Error bars indicate SEM.
Gettler et al. PNAS
September 27, 2011
vol. 108
no. 39
spent in childcare as fathers (at follow-up) was not predicted by
either AM T [ordered logistic OR = 1.12, 95% condence in-
terval (CI): 0.841.48; P= 0.441] or PM T (OR = 0.89, 95% CI:
0.671.18; P= 0.417) measured at baseline.
Among the men in our sample who were single nonfathers as
young adults, those with higher waking T were more likely to
have become a partnered father by the time of follow-up. Once
these men entered stable partnerships and became new fathers,
they subsequently experienced a large decline in T, which was
greater than the comparably modest declines seen in single
nonfathers during the same period. Finally, fathers who were
most involved in childcare had lower T compared with fathers
who did not participate in care. Using longitudinal data, these
results demonstrate that high T not only predicts mating success
(i.e., partnering with a female and fathering a child) in human
males but that T is then greatly reduced after men enter stable
relationships and become fathers. The nding that high in-
volvement in childcare was associated with low T measured at
follow-up but was not related to baseline T supports the hy-
pothesis that direct care of dependent offspring suppressed T
among the fathers in our sample (20, 22). Our ndings suggest
that human males have an evolved neuroendocrine architecture
that is responsive to committed parenting, supporting a role of
men as direct caregivers during hominin evolution (13, 14, 21).
Our results provide longitudinal evidence that high T predicts
subsequent mating success in human males. Although we did not
measure the behavioral or physical pathways linking T with
mating success in this analysis, T has previously been shown to
bolster traits related to mating effort and attractiveness, such as
musculature (1, 28, 29), motivation to win during competition
(30), and pursuit of social dominance (2, 31). Men with higher T
have also been shown to have physical attributes deemed at-
tractive by females and to have more recent and lifetime sexual
partners (3234). Although families traditionally played a pri-
mary role in arranging courtship and marriage in the Philippines,
courting in recent decades has gradually moved toward males
and females meeting independent of familial control (35). Mens
romantic prospects may thus be increasingly contingent on male-
male competition, particularly in social and economic domains
(36). This trend has likely increased the potential for high T to
factor into male mating success.
Although helpful in securing mates, many T-stimulated
behaviors may conict with partnership stability and parenting
(4, 33). Indeed, men with higher T have been shown to be more
likely to have marital problems and to be divorced (4, 18),
whereas men with lower T have been found to spend more time
with their wives (21). In an experimental setting, men with
greater T also reported feeling less sympathy or need to respond
to infant cries compared with men with lower T (37). Although
prior cross-sectional studies have led to speculation that father-
hood decreases T in human males (19, 22, 24), our longitudinal
results demonstrate that fatherhood causes T to decline and
remain low. These ndings were not substantively changed when
covariates (psychosocial stress and sleep quality) that might be
expected to mediate the relationship between fatherhood/
marriage and T were included in models and are consistent with a
previous longitudinal report that men who were married experi-
enced decreased T (18).
We also found that T at follow-up was lowest among fathers
reporting more hours spent in childcare. Although this nding
could result if men with low T at baseline were more likely to get
involved in childcare, instead, we found that childcare in-
volvement was unrelated to T at baseline. Familial composition
was not a confounding inuence on the relationships that we
documented, which is consistent with previous research from
Cebu reporting that fathers did not alter their childcare partici-
pation based on their number of children (38). Together, these
ndings provide longitudinal support for the hypothesis that
interacting with a dependent child suppresses T (20, 22, 24). In
prior research conducted in two neighboring cultural groups in
Tanzania, fathers in the population in which paternal care is the
cultural norm had lower T, whereas this was not found among
fathers in the group in which paternal care is absent (20). In
a study of a polygynous Senegalese society, it was found that
fathers who were highly invested in their children, as reported by
the childrens mothers, had lower T compared with fathers who
were less invested (24). Lower T has also been associated with
nurturing behaviors among fathers (37, 39).
Fig. 2. Between-group changes in AM and PM T values between 2005 and
2009 with fathers stratied by child age. Values are adjusted for time of
saliva collection and usual wake time (AM) and are derived from regressing
the change in T on fatherhood, stratied by child age, with men who were
not fathers in 2005 and 2009 as the comparison group, and controlling for
sleep quality and psychosocial stress (Tables S5 and S6). Fathers of newborns
were men whose youngest child was in the perinatal period [1 mo (m) old or
less]. Fathers of infants were men whose youngest child was older than 1 mo
(m) but 1 y (yr) old or less. ^P<0.10; **P<0.01; ***P<0.001. Error bars
indicate SEM.
Fig. 3. 2009 AM and PM T values among fathers varying in daily physical
childcare. Values were derived from regressing T on daily paternal caregiv-
ing, controlling for time of saliva collection, usual wake time (AM), sleep
quality, psychosocial stress, and number of children, with fathers who
reported no involvement in childcare as the comparison group. No care (n=
34), 01h(n= 37), 13h(n= 139), 3+ h (n= 102). Regression models were
calculated with robust SEs.
P= 0.020;
P= 0.044;
P= 0.015. AM model: R
0.047; PM model: R
= 0.046. Error bars indicate SEM.
| Gettler et al.
Although all new fathers had lower T than men remaining
single nonfathers, our results also suggest that fathers of new-
borns (1 mo old or less) experienced a large transient decline in
T that was signicantly greater than that of fathers whose
youngest child was older than 1 mo of age. This nding is con-
sistent with a previous cross-sectional study in which fathers of
newborns were found to have lower T compared with a group of
expectant fathers, whose T had been measured during their
partnerspregnancies (39). In another study in which expectant
fathers were sampled for T multiple times during their partners
pregnancies and after the women gave birth, those men with high
T during the pregnancy showed a signicant decline in the rst
week after birth (40). Viewed alongside these past ndings, the
steep transient T decrease that we document among fathers with
newborns could indicate an anticipatory psychological compo-
nent to mens T decline around the time of birth of their chil-
dren. Alternatively, our control variables may not fully capture
the scope of sleep disruption and psychosocial adjustments that
accompany a familys accommodation of a newborn baby, which
could contribute to this large short-term T decline in the post-
partum period. Taken together, our ndings suggest that antic-
ipatory or other effects unique to the immediate period of
parturition are likely additive to the more sustained effects of
caregiving in suppressing paternal T.
Our results are consistent with ndings from many bird spe-
cies, among which fathers often show declines in T during
periods in which they help raise young (6, 41). Relevant ndings
from other mammals are less consistent, with fathers having
lower T in some (4245) but not all (4648) mammalian species
in which fathers assist with offspring care. Analogies to bird and
other mammalian species are somewhat constrained because
humans are not seasonal breeders and have signicantly longer
interbirth intervals (34 y) and slowly developing dependent
offspring (49, 50). Moreover, human malespredisposition to-
ward paternal care is likely a derived trait that emerged during
hominin evolution (1315, 51, 52). Thus, compared with other
species with paternal care, mens T might decrease with father-
hood and then remain low over a longer and more sustained time
period corresponding to the slow life history of humans and the
prolonged dependency of offspring (50, 53, 54).
There is considerable interest in the health differentials be-
tween fathers and single men (55), and it is often reported that
married men and fathers have lower risk for certain diseases and
mortality (5658). Our ndings suggest that fathers are likely
exposed to lower levels of T throughout much of their prime
reproductive years, which could contribute to some of these
health differentials. For instance, high T may increase risk for
prostate cancer and adverse cholesterol proles, and high T has
also been linked to risk-taking behaviors that can affect mens
health, such as drug and alcohol use and promiscuity (33, 59, 60).
Our nding that men who end up as fathers tend to have higher
T to begin with also suggests that some of the benets of low T
among fathers could be offset by higher T exposure among these
men before becoming fathers, which could hinder efforts to
identify the health impacts of being a partnered father. Thus, our
ndings point to likely health effects of fatherhood and also
underscore some of the complexities of this exposure. The large
reductions in circulating T among the new fathers in our sample
provide a strong rationale to investigate linkages between fa-
therhood status and risk for diseases related to T exposure.
In sum, our results provide longitudinal conrmation that T
exhibits a bidirectional relationship with reproductive strategy in
human males. Single nonfathers with higher T at baseline were
more likely to be partnered fathers 4.5 y later. After becoming
partnered fathers, these men experienced dramatic reductions
in both waking and evening T, which were substantially greater
than the age-related declines observed in single nonfathers. Our
nding that caregiving fathers had lower T than fathers who did
not invest in care supports the hypothesis that father-child in-
teraction likely contributes to suppressed paternal T among fathers.
Table 1. Sample characteristics stratied on low and high follow-up (2009) AM T (n= 624)
All (n= 624) Low AM T* (n= 316) High AM T* (n= 308)
Mean ±SD Mean ±SD Mean ±SD Pvalue
Demographic characteristics
Age, y 26.0 ±0.3 26.0 ±0.3 26.0 ±0.3 0.57
Highest grade completed 11.5 ±4.8 11.2 ±4.8 11.9 ±4.8 0.07
T values
AM T 2005, pg/mL 192.8 ±74.1 175.5 ±65.7 210.5 ±77.9 0.0001
AM T 2009, pg/mL
162.0 ±61.8 115.9 ±30.8 209.2 ±48.4 0.0001
PM T 2005, pg/mL 117.7 ±51.9 112.3 ±50.0 123.3 ±53.2 0.0001
PM T 2009, pg/mL
92.6 ±39.2 79.3 ±32.4 106.2 ±40.9 0.0001
Anthropometric measures
Body fat percentage 20.1 ±5.2 19.9 ±5.3 20.2 ±5.1 0.40
Body mass index, kg/m
22.7 ±3.6 22.5 ±3.8 22.9 ±3.4 0.23
Relationship characteristics
Partnered 2005 19.7% 20.6% 18.8% 0.59
Partnered 2009 54.0% 59.8% 48.1% 0.003
Duration of relationship
,y 3.7±2.4 3.6 ±2.4 3.8 ±2.4 0.45
Fatherhood characteristics
Father 2005 16.0% 15.8% 16.2% 0.89
Father 2009 50.0% 56.0% 43.8% 0.002
No. children
1.6 ±0.8 1.6 ±0.8 1.7 ±0.8 0.18
Age of oldest child
,y 3.4±2.2 3.2 ±2.2 3.6 ±2.2 0.16
*Test for signicant differences by median split of 2009 AM T (low AM T <155.6 pg/mL <high AM T); unpaired,
two-tailed ttest or χ
Paired ttests comparing 2005 and 2009 AM and PM T (both P<0.0001).
Restricted to partnered men in 2009 (n= 337).
Restricted to fathers in 2009 (n= 312).
Gettler et al. PNAS
September 27, 2011
vol. 108
no. 39
These results point to an important role of the hypothalamic-
pituitary-gonadal axis as a mediator of the tradeoff between
investments in parenting and mating in human males, similar to
what is seen in other species in which paternal care is common.
They also add to evidence that human males have an evolved
neuroendocrine architecture shaped to facilitate their role as fa-
thers and caregivers as a key component of reproductive success.
Study Population. Data were collected in 2005 and 2009 as part of the CLHNS,
a representative population-based birth cohort study of mothers and their
infants born in 19831984 (61). Men (n= 624) were an average of 26.0 ±0.3
(SD) y old at the time of data and sample collection in 2009. Socioeconomic,
demographic, and behavioral data were collected during in-home interviews
administered by Cebuano-speaking interviewers (61). Men were classied as
partneredif they identied themselves as married or in a cohabitating
relationship (22). Fathers were dened as men who reported having one or
more biological children. Fathers of newborns were dened as men whose
youngest child was in the perinatal period (1 mo old or less). Fathers of
infants were dened as men whose youngest child was older than 1 mo of
age but less than 1 y old. Paternal caregiving was assessed via the question,
How much time do you usually spend providing physical care to your
children on a daily basis?with men grouped by no contact/0 min, less than
1h,13 h, and 3+ h.
Weight (kg), height (cm), and triceps skinfold thickness (mm) were
measured using standard anthropometric techniques (62). Body fat per-
centage was calculated from triceps skinfold thickness using body density
estimates and a body composition predictive equation (63). The body mass
index was calculated as the ratio of weight (kg)/height (m
). Self-reported
psychosocial stress in the month preceding sampling was quantied via
a modied version of the 10-item Perceived Stress Scale (PSS) (64). Sleep
quality was assessed via self-reports of how many days per week subjects
woke up feeling rested. This research was conducted under conditions of
informed consent with human subject clearance from the Institutional Re-
view Boards of the University of North Carolina at Chapel Hill and North-
western University.
Salivary T Collection and Measurement. The same saliva collection procedures
were used in 2005 and 2009. Each participant was provided with instructions
and two polypropylene tubes for saliva collection. The rst sample was
collected immediately before bed (PM) at mean sampling times of 10:14 PM ±
1:38 (SD) in 2005 and 10:04 PM ±1:33 (SD) in 2009. The participants were
instructed to collect the second sample immediately on waking the follow-
ing morning (AM) and to report the time of saliva collection. Mean AM
sampling times were 6:30 AM ±1:13 (SD) in 2005 and 6:48 AM ±1:28 (SD) in
2009. Saliva tubes were collected on the second day by an interviewer and
stored at 35 °C until shipment on dry ice to Northwestern University, where
they were stored at 80 °C.
Salivary T Assessment. T concentrations were determined at the Laboratory
for Human Biology Research at Northwestern University using an enzyme
immunoassay protocol developed for use with saliva samples (kit no. 1-2402;
Salimetrics). Interassay coefcients of variation were 13.7% and 11.5% for
high and low control samples, respectively, in 2005 samples and 7.8% and
17.9% for high and low control samples, respectively, in 2009 samples.
Sample Selection. During a 1-y period in 19831984, the CLHNS surveyed
w28,000 households in randomly selected neighborhoods in metro Cebu
City, inviting all pregnant women to participate (acceptance rate of 96%, n=
3,080 singleton liveborns). Thus, the original sample was representative of
births during that year. Subsequent attrition has largely been attributable to
out-migration, and the refusal rate for the subjects in adult surveys has
typically been w5% (61). During the 2005 survey, 1,008 (62%) of the original
cohort of 1,633 liveborn males were located and were willing to be inter-
viewed, and 908 (56% of original cohort) men were located and enrolled in
2009. Subjects lost to attrition have generally been from higher socioeco-
nomic status households (61), which is also true of the present sample (see
below). Participants were compensated 100 pesos (w$2 US) for their time.
Anal sample of 624 individuals had all required data and met all criteria
for inclusion. Seventy-three men were excluded from this analysis because
they were nightshift workers or had sleep patterns consistent with night-
shift work, which is associated with disrupted circadian rhythms for T (65,
66). Four subjects were excluded as outliers because their T values were very
high (all were 6+ SD above the sample mean), suggesting contamination of
the saliva sample by blood, and one subject was excluded because of a T
value below the assay detection limit. Because this sample is drawn from
a cultural setting in which it is rare for men to become new fathers outside
of stable romantic partnerships or to le for divorce, there were few single
new fathers (n=12)ordivorcedmen(n= 9), who therefore were excluded
from longitudinal analyses. We assessed whether subjects in the analysis
differed from excluded men. Excluded individuals were born to mothers
(P<0.10) and fathers (P<0.01) who were more educated. However, there
were no signicant differences between the subsample used here and
the original baseline cohort in birth weight, birth length, birth order,
household income, parental height, or mother or fathers age at baseline
(all P>0.10).
Statistical Analysis. All analyses were conducted using version 10 of Stata
(Stata Corporation). AM T (pg/mL), PM T (pg/mL), sleep quality, and PSS were
all analyzed as continuous variables. AM and PM T were each adjusted for
time of sampling (AM and PM) and usual wake time (AM) before calculating
absolute change in T (ΔT) between baseline (2005) and follow-up (2009). All
other models were also adjusted for time of sampling (AM and PM) and
usual wake time (AM). Average self-reported stress and sleep quality were
calculated as the mean of 2005 and 2009 values (26).
Paired ttests were used to compare adjusted values of baseline T and
follow-up T. Multiple logistic regression was used to predict 2009 partner-
ship and fatherhood status from baseline T (z-scored) among men who were
single or were not fathers in 2005. Multiple linear regression was used to
predict ΔT based on partnership and fatherhood status changes between
2005 and 2009, controlling for sleep quality and self-reported stress, among
men who were single nonfathers at baseline. Multiple linear regression was
used to predict ΔT among men who were single nonfathers at baseline,
based on the age of fathersyoungest child at follow-up, with child age
stratied according to whether the youngest child was a perinatal infant (1
mo old or less), nonperinatal infant (older than 1 mo but less than 1 y), or
noninfant (older than 1 y). Multiple linear regression was also used to assess
differences in fathersT values (2009) based on self-reported hours spent in
direct physical childcare. Ordered logistic regression was used to predict
mens self-reported hours spent in direct physical childcare (2009) from
baseline T (z-scored) among men who were single nonfathers in 2005, with
all models meeting the parallel regression assumption based on the Brant
test. Statistical signicance was evaluated at P<0.05, with relationships with
0.05 <P<0.10 interpreted as a borderline statistical trend. All regression
models were tested for heteroscedasticity using the BreuschPagan/Cook
Weisberg test and were calculated with robust SEs where appropriate.
ACKNOWLEDGMENTS. Linda Adair played a central role in designing and
implementing the CLHNS survey from which these data and samples were
obtained. Greg Duncan provided statistical advice. Jeffrey Huang helped
with laboratory work. We thank the Ofce of Population Studies, University
of San Carlos, Cebu, Philippines, for its role in study design and data
collection and the Filipino participants who provided their time for this
study. This work was supported by the Wenner Gren Foundation (Grants
7356 and 8186), National Science Foundation (Grants BCS-0542182 and BCS-
0962212), Interdisciplinary Obesity Center (Grant RR20649), and Center for
Environmental Health and Susceptibility (Grant ES10126; Project 7-2004-E).
L.T.G. was supported by a National Science Foundation Graduate Research
Fellowship during write-up.
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vol. 108
no. 39
... Consistent with the idea that testosterone may affect reproductive potential by reducing choosiness in single men, higher concentrations of the hormone have been linked with more self-reported (lifetime) sexual partners, both in older adults (Pollet et al., 2011) and in younger student samples (Peters et al., 2008). In a longitudinal study, single men with higher (vs lower) testosterone concentrations at the beginning of the study period were more likely to be partnered and have children four and half years later (Gettler et al., 2011). Perceptions of attractiveness may explain these links: men are more romantically interested in women that they perceive as higher in attractiveness (Eastwick et al., 2014) and, here, testosterone boosted the appeal of less attractive women to single men, potentially widening the mating market and enhancing reproductive potential. ...
... Perceptions of attractiveness may explain these links: men are more romantically interested in women that they perceive as higher in attractiveness (Eastwick et al., 2014) and, here, testosterone boosted the appeal of less attractive women to single men, potentially widening the mating market and enhancing reproductive potential. More generally, testosterone drives trade-offs between mating and parental effort, with concentrations of the hormone decreasing after partnering and having children, especially among men who dedicate more (vs less) time to childcare (Gettler et al., 2011;Grebe et al., 2019). Conversely, married men with higher concentrations of testosterone are more likely to commit infidelity (Fisher et al., 2009), experience dissolution, and eventually remarry (Pollet et al., 2011) (also see Alvergne et al., 2009;Booth and Dabbs, 1993). ...
... Testosterone has been linked to mating-effort across multiple domains (recent reviews in Geniole and Carré, 2018;Gray et al., 2017;Zilioli and Bird, 2017), but little is known about the proximal mechanisms through which it acts. We provide evidence that a single dose of testosterone modulates perceptions of attractiveness, changes that may explain previously reported links between the hormone and promiscuity, infidelity, and relationship dissolution (e.g., Gettler et al., 2011;Peters et al., 2008;Pollet et al., 2011). Because this simple perception is a powerful determinant of other, downstream judgements and can bias the way we treat and value others (meta-analysis in Langlois et al., 2000), these results have wide implications. ...
Full-text available
Attractiveness judgements influence desires to initiate and maintain romantic relationships. Testosterone also predicts relationship initiation and maintenance; such effects may be driven by the hormone's modulation of attractiveness judgements, but no studies have investigated causal (and situation-dependent) effects of the hormone on these judgements. Using a placebo-controlled cross-over design, our preregistered analyses revealed order- and relationship- dependent effects: single heterosexual men judged the women as more appealing when testosterone was administered first (and placebo second), but marginally less appealing when placebo was administered first (and testosterone second). In a more complex model incorporating the women's attractiveness (as rated by an independent set of observers), however, we show that testosterone increases the appeal of women -but this effect depends upon the men's relationship status and the women's attractiveness. In partnered men (n = 53) who tend to derogate attractive alternatives (by rating them as less appealing), testosterone countered this effect, boosting the appeal of these attractive alternatives. In single men (n = 53), conversely, testosterone increased the appeal of low-attractive women. These differential effects highlight the possibility of a newly discovered mechanism whereby testosterone promotes male sexual reproduction through different routes depending on relationship status, promoting partner up- rather than down-grading when partnered and reducing choosiness when single. Further, such effects were relatively rapid [within 85 (±5) minutes], suggesting a potential non-genomic mechanism of action.
... Other landmark longitudinal studies in this area have similarly focused on the significance of this transition and fathers' hormonal changes across their partners' pregnancies (Edelstein et al., 2017), around birth (Kuo et al., 2018), and in the newborn period (Gettler et al., 2011) and how men's hormones relate to their care for their children and support of their partners during this critical time frame. A number of the articles in this special issue build from this foundation to evaluate new questions about the intersection between fathers' physiological and neural function with care, cognition, and social bonding in the prenatal, peripartum, infancy periods, and beyond. ...
... In a study following U.S. fathers from the prepartum through infancy, Corpuz et al. (2021) found that new fathers' testosterone (T) began to rebound following the first few months of the postpartum. Aligning with prior research linking lower T and greater paternal care (Edelstein et al., 2017;Gettler et al., 2011), they found that fathers' whose T rebounded more steeply were less involved in caregiving, although notably, fathers with more rapidly rebounding T engaged in higher quality care during a challenging parenting task. Ahnert et al. (2021) also found that Austrian fathers with greater diurnal declines in T engaged in more nurturant, sensitive caregiving and had stronger father-child attachment; however, fathers whose T declined less across the day participated in more rough and tumble play, which is often emphasized as a pathway by which fathers affect child development. ...
... Males too undergo transitions. Testosterone diminishes in bachelors who marry and even further after they father children (Gettler, McDade, Feranil, & Kuzawa, 2011;Gray, Kahlenberg, Barrett, Lipson, & Ellison, 2002). Because the studies we found do not define sex/gender and treat it as binary, we cannot specify which characteristics of sex/gender relate to self-protection. ...
The target article presented a plausible argument that females' susceptibility to threats might be self-protection for staying alive, but some evidence requires scrutiny. We need to consider (1) the biases of narrative reviews, (2) subjective life quality, and (3) the shadow side of extreme reactions to threats before concluding that females' threat-based response is a self-protection mechanism that promotes survival.
... The scarcity of studies on fathers' AVP is in contrast with the relative abundance of studies on fathers' T levels. Studies using between-subject designs have pointed to lower T in fathers compared to non-fathers, as evident from two meta-analyses [21,22], and the (only) two within-subject studies following fathers from the prenatal to the postnatal phase [23,24] partly confirm this effect. Such within-subject studies are the more important as the results of Grebe et al. [21] highlight that part of the difference in T between fathers and non-fathers is explained by fathers being more often in a close partner relationship, which in and of itself seems related to lower T. ...
How do hormonal levels in men change from pregnancy to after the birth of their firstborn child, and what is the role of oxytocin, alone or in interplay with other hormones, in explaining variance in their parenting quality? We explored in 73 first-time fathers the development of five hormones that have been suggested to play a role in parenting: oxytocin (OT), vasopressin (AVP), testosterone (T), oestradiol (E2) and cortisol (Cort). In an extended group of fathers ( N = 152) we examined associations with fathers’ behaviour with their 2-month-old infants. OT and E2 showed stability from the prenatal to the postnatal assessments, whereas AVP and T decreased significantly, and Cort decreased marginally. OT on its own or in interplay with other hormones was not related to paternal sensitivity. Using an exploratory approach, the interaction between T and E2 emerged as relevant for fathers’ sensitive parenting. Among fathers with high E2, high T was associated with lower sensitivity. Although we did not find evidence for the importance of OT as stand-alone hormone or in interplay with other hormones in this important phase in men's lives, the interaction between T and E2 in explaining variation in paternal behaviour is a promising hypothesis for further research. This article is part of the theme issue ‘Interplays between oxytocin and other neuromodulators in shaping complex social behaviours’.
... Instead, males' behavioral priorities shift toward mate attraction and extra pair mating effort (11,40). In humans, there is evidence that fathers with lower T provide more nurturant, direct care of children, engage in less marital conflict, and have higher relationship quality with their partners, compared to fathers who have higher T (28,(41)(42)(43)(44)(45)(46). These patterns point to the importance of these hormonal shifts as social roles change across life-history transitions, as well as to potential fitness benefits through more cohesive partnerships and improved child health and development outcomes (13,39,47). ...
SignificanceTestosterone influences how animals devote energy and time toward reproduction, including opposing demands of mating and competition versus parenting. Reflecting this, testosterone often declines in new fathers and lower testosterone is linked to greater caregiving. Given these roles, there is strong interest in factors that affect testosterone, including early-life experiences. In this multidecade study, Filipino sons whose fathers were present and involved with raising them when they were adolescents had lower testosterone when they later became fathers, compared to sons whose fathers were present but uninvolved or were not coresident. Sons' own parenting behaviors did not explain these patterns. These results connect key social experiences during adolescence to adult testosterone, and point to possible intergenerational effects of parenting style.
... Men's level of testosterone falls, and their level of prolactin rises when their mate becomes pregnant and when the baby is born (Storey et al., 2000). The greater these changes, the more paternal behavior the father exhibits (e.g., Gettler et al., 2011). Thus, parental behavior is shaped partly by hormones and experience in both sexes, but the hormones differ. ...
Full-text available
Developmental Psychology is the branch of psychology that studies, not only human behavior, but how and why human behavior changes over time. This essay seeks to review to what extent Developmental Psychology has failed to perceive human behavior through the lens of evolutionary theory in general, and in particular sexual selection as first described by Darwin and later elaborated on by many, including Robert Trivers and Geoffrey Miller; the essay asserts that this failure has resulted in many wrong turns and missed opportunities. In some cases, major developmental theorists (e.g., Freud, Erikson) were bedeviled by sex-based differences which they saw but could not explain and which compromised the parsimony of their stage theories. In the case of stage theories of moral development, some major theorists (e.g., Piaget, Kohlberg) were able to offer simpler explanations of moral development only by limiting their studies to male subjects. And, while Developmental Psychology textbooks thoroughly describe sex differences in the timing of morphological changes in puberty, writers seldom discuss why the timing is different in the two sexes, universally, and functionally. On the other hand, several domains of developmental focus, including play, mate choice, parenting, and spatial cognition, have seen successful research efforts that utilized sexually selected predispositions as foundational assumptions. The essay concludes with a discussion of how a more evolutionary and functional view of human behavior might move the field of Developmental Psychology to an even more robust and accurate understanding of how humans change over the course of a lifetime.
... More often studied in relation to paternal caregiving is the hormone T. T is the end product of the hypothalamic-pituitary-gonadal (HPG) axis and is critical for reproductive, sexual and dominance behavior (Bos, 2017). In general, fathers have lower T compared to non-fathers (Gettler et al., 2011;Grebe et al., 2019;Perini et al., 2012). This T downregulation is suggested to reflect a shift away from mating and towards parenting effort, and suggested to be adaptive since higher T concentrations are associated with aggression and less empathy (Carré et al., 2011;Hermans et al., 2006). ...
Given that parental caregiving quality affects child development from birth onwards, it is important to detect parents who are at risk for low-quality caregiving as early as possible, preferably before or soon after birth. This study investigated whether cortisol (CORT) and testosterone (T) measured during the last trimester of pregnancy and six weeks postpartum were associated with observed caregiving quality at child age 3 in mothers (N = 63) and fathers (N = 45). CORT and T were measured during an interaction with a simulator infant (pregnancy) and their own infant (postpartum). In mothers, no associations were found with CORT and T during pregnancy, but higher postpartum CORT during a mother-infant interaction was related to higher caregiving quality during toddlerhood. In fathers, the association between T during pregnancy and caregiving quality in toddlerhood was more negative for fathers with low CORT. In contrast to mothers, higher postpartum CORT in fathers was associated with lower caregiving quality in toddlerhood. These findings proved robust after applying the Benjamini–Hochberg procedure to control for false discovery rate. Our findings indicate that CORT and T during the perinatal period can forecast caregiving quality in both mothers and fathers. Moreover, our results provided evidence for the dual-hormone hypothesis, but only in fathers. These findings contribute to our growing understanding on how endocrine measures explain individual differences in caregiving quality in mothers and fathers.
... Changes in mental states and behaviour may be explained by differential binding of endogenous (changing concentrations) as well as exogenous sex steroids (due to different binding properties) to receptor sites of brain regions involved in socio-emotional processing (frontal cortex and limbic areas) [10,63]. But individual difference in the circulating and pharmacologically-manipulated levels of testosterone are often weak predictors of individual differences in social behaviours [3,6,26]. Previous studies linked testosterone with competitive, aggressive, strategic, and dominance behaviours. ...
Full-text available
Although there is evidence that testosterone has deteriorating effects on cognitive and affective empathy, whether testosterone administration influences both routes to understanding others has not yet been simultaneously investigated. We conducted a functional magnetic resonance imaging (fMRI) pharmacological study using a within-subjects, randomized placebo-controlled double-blind crossover design to examine the effects of 100 mg transdermal testosterone administration on brain activation during a task that examines affective and cognitive empathy simultaneously in a sample of 23 healthy right-handed adult men. Relative to placebo, testosterone did not alter affective or cognitive empathy functional brain networks. Instead, the task yielded activation in the canonical networks associated with both types of empathy. Affective empathy yielded activation in the inferior and middle frontal gyri, inferior temporal gyri, and the cingulate cortex. Cognitive empathy was associated with activation of the temporoparietal junction, medial prefrontal cortex, middle and inferior temporal gyri, and temporal pole. Behaviourally, testosterone administration decreased error rates and increased participants’ confidence in their responses regardless of response accuracy. Independent of testosterone administration, participants reported higher affective responses during emotionally negative scenarios. Even though our results provide further evidence that testosterone administration in healthy men does not alter brain activity underlying cognitive and affective empathy, testosterone administration does influence the empathic concern and hence socio-cognitive processes. The reproducibility and variability of the current and previous findings should nevertheless be addressed in upcoming studies.
Introduction. Scientific study of religious aspect of fatherhood is actual due to the significance of the man’s role in sustainability of parental and family relations in conditions of a demographic crisis. The aim of the article is to analyze a range of reproductive, generative and marital behavior of men defined by their religious identification as a factor that influences the formation of a family image that is shared in traditional religions. Materials and Methods. Empirical basis of the study includes data of social survey held by authors in two subjects of Russian Federation – in the Republic of Tatarstan and Vologda Region. The object of the study – men at the age of 18‒49, the sample – 1 353 men. Use of comparative, economic-statistical and factor methods of analysis allowed to define the level of the influence of men’s religious identity on their generative behavior. Results. The calculation of average values has defined comparative superiority of the value of the family in comparison with the value of work in all subgroups of the surveyed men, regardless of their involvement in the religious context, however, among religious men the family in the structure of life values is more vivid. Some peculiarities of the role distribution in families, expectations towards the number of children in the family, orientation towards upbringing and complicity in the growing up of children in the family, determination of the image of a father and correspondingly behavior of the respondents were determined. Men’s religious identity influences their desire to have bigger number of children: Christians tend to have two children while Muslims want to have more than two children. The percentage of men who desire to become a father of many children is less among those who don’t believe in God. Discussion and Conclusion. The study of the influence of men’s religious identity on generative behavior allowed to reveal factors causing formation of reproductive behavior. This data will help to work out measures to increase the birth rate into account the role of fatherhood institute and confessional identity of a man. Results of the research can be used in the process of developing measures for the implementation of demographic and family policy.
Rising numbers of young unmarried men in India reflect a marriage squeeze that goes beyond the shortage of brides created by sex-selective abortion. We describe a decline in men's marriageability caused by their falling economic prospects at the same time as families of brides are increasingly seeking grooms with stable employment. We group young men into those without jobs or much education, those with education but no work, and the privileged few with education as well as employment. This classification resolves some of the seeming contradictions in the qualitative literature on marriage in India. Some of this literature talks about the rising prevalence of bride price and some about the persistence of dowry, while some papers reflect in general on the costs of being young, male, and aimless. Our commentary includes a review of the growing literature on the physiological and (perhaps) consequently behavioural and health outcomes of men's anomie.
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A combination of field and laboratory investigations has revealed that the temporal patterns of testosterone (T) levels in blood can vary markedly among populations and individuals, and even within individuals from one year to the next. Although T is known to regulate reproductive behavior (both sexual and aggressive) and thus could be expected to correlate with mating systems, it is clear that the absolute levels of T in blood are not always indicative of reproductive state. Rather, the pattern and amplitude of change in T levels are far more useful in making predictions about the hormonal basis of mating systems and breeding strategies. In these contexts we present a model that compares the amplitude of change in T level with the degree of parental care shown by individual males. On the basis of data collected from male birds breeding in natural or captive conditions, polygynous males appear less responsive to social environmental cues than are monogamous males. This model indicates that there may be widely different hormonal responses to male-male and male-female interactions and presumably equally plastic neural mechanisms for the transduction of these signals into endocrine secretions. Furthermore, evidence from other vertebrate taxa suggests strongly that the model is applicable to other classes
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We examine data from a national survey of 15 – 27 year olds in the Philippines to assess attitudes toward marriage and cohabitation, and we analyze the marital and nonmarital union experiences of 25 – 27 year olds. We find that attitudes toward cohabitation remain quite conservative among young Filipinos, although men view cohabitation more favorably than do women. We also find that men’s socioeconomic status affects their ability to enter unions, particularly marriage, whereas women’s union formation patterns are influenced by the family in which they grew up, their participation in religious services, and to some degree by their place of residence. Both men and women who hold more liberal attitudes on a range of issues are more likely to have cohabited than are individuals who do not share those views. For now, however, we do not expect cohabitation to become a widespread substitute for marriage in the Philippines.
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Two hypotheses have been offered to explain the relation between testosterone and antisocial behavior in delinquent and criminal populations. One is that testosterone leads directly to antisocial behavior. The other is that a constellation of dominance, competitiveness, and sensation seeking associated with testosterone leads to either antisocial or prosocial behavior, depending upon an individual's resources and background. Analysis of archival data from 4,462 U.S. military veterans supported the first hypothesis: Testosterone was correlated with a variety of antisocial behaviors among all individuals. However, socioeconomic status (SES) proved to be a moderating variable, with weaker testosterone-behavior relationships among high SES subjects.
While it is obvious that a birth will increase a woman's time devoted to child care, it is less obvious where the additional time comes from. Using data from the Philippines, the author estimates the average time spent in child care, market work, housework, and leisure by mothers, fathers, and older children both before and after the birth of a child. Comparison of the effects of the birth on time allocation across households indicates that the time adjustments made after the birth of a first child are significantly greater than those made after the births of subsequent children. The results also indicate that mothers bear over 90 percent of the time costs of children in families with no older children. When older children are present, however, mothers' percentage contribution falls considerably.
National survey data are used to compute mortality rates for persons in different living arrangements. Mortality is lower for married persons than for nonmarried persons; lower for married persons with children than for those without children; and lower for nonmarried persons who are household heads than for those who are not heads. Two approaches are considered: (1) social processes select healthy persons to the statuses of spouse, parent, and household head; (2) those statuses protect their occupants against risk of death. The protection hypothesis succeeds better than the selection hypothesis in accounting plausibly for the sex and age pattern of status differences in mortality.
We examine the relationship of testosterone to tendencies to marry and divorce, and to the quality of marriage, of a large representative sample of men. The analysis shows that men producing more testosterone are less likely to marry and more likely to divorce. Once married they are more likely to leave home because of troubled marital relations, extramarital sex, hitting or throwing things at their spouses, and experiencing a lower quality of marital interaction. Sociological models that might be informed by this finding are examined, and its implications for subsequent research are discussed.
controversial. Important unanswered questions include: 1) the role of the timing of economic deprivation during childhood, especially poverty very early in life; and 2) how to obtain estimates of the effects of income from survey data that are free from the confounding effects of unmeasured aspects of the home and neighborhood environments. After summarizing findings from recent contributions to this literature, we engage in new analyses of data from the Panel Study of Income Dynamics relating children's completed schooling and nonmarital fertility to income during middle childhood, adolescence, and, for the first time, very early childhood. They suggest that economic conditions in early childhood clearly matter the most and that income effects are nonlinear, with the largest impact associated with increments to very low incomes. A second analysis addresses the issue of unmeasured heterogeneity by using PSID siblings to relate sibling differences in completed schooling to sibling differences in stage-specific family income. Although estimated with less precision, results from this analysis also suggest that economic conditions in early childhood affect child development.