Analysis of data from a questionnaire survey of 2,000 young Malians undertaken by the authors in 2002 demonstrates that, even in underprivileged urban and rural populations, changes in sexual behavior are emerging. Among women, first sex and motherhood are taking place slightly later, and a minority is now dissociating sexuality and procreation. Our data confirm the considerable impact of female education on this transition. Girls' sexual activity before procreation is also influenced by lower religiosity. Among men, in contrast, in a traditional context of late sexual debut and fatherhood, the trend is toward earlier sexual activity and procreation. Fatherhood is delayed, however, among better-educated, wealthier, and less religious urban men, who therefore experience a longer period of sexual activity before they begin to build their own families. The study concludes with an analysis of the possible association of the sexual transition with young people's increased vulnerability resulting from their adoption of risky sexual behaviors and from unfavorable conditions surrounding the arrival of their first child.