Recent work with samples of black and white urban American women showed a clear behavioral sequence relating age at menarche to age at first intercourse to age at first birth. This paper shows that the linking of ages at menarche, intercourse, marriage, and first birth is a pattern which occurs in very diverse cultures. We present confirmatory data from the United States, Belgium, and Pakistan, and from Malay and Chinese women in Malaysia. We interpret our findings as indicating a biological process leading to (a) social interpretations of readiness for reproduction, and (b) persisting biological differences between early and late maturing women.