Abstract In this paper, we describe and utilize methods to estimate the consequences,for,children's,schooling,and,birthweight,of the,exogenous variability in the supply of births in one low income country, Malaysia. The method,utilizes,information,on,contraceptive,techniques,employed,by,couples,to estimate,directly,the,technology,of,reproduction,and,provides,a means,of disentangling,the biological,and demand,factors,that,contribute,to the variation in,fertility,across,couples,under,a regime,of,imperfect,fertility,control.,Our results,suggest,that,imperfect,fertility,control,significantly,influences,both the average schooling attainment and birthweight of children in Malaysia, with couples,having,above-average,propensities,to,conceive,reporting,higher,levels,of actual fertility, significantly lower expectations of and actual schooling attainment for their children, and lower birthweight children, on average, due to,smaller,intervals,between,births. Correspondence,to:,Mark,R. Rosenzweig