In this article, the authors study the effects of family formation on criminal careers for 540 high-risk men and women in the Netherlands. In a prospective design, spanning 21 years, the authors analyzed complete data on offending, marriage, parenthood, and a large set of background information. Random effects were used to model the relation between family-life events and offending, controlling for possible confounders. Findings for men support the hypothesis that marriage promotes desistance from serious offending. Males additionally benefit from parenthood, and from having a first child in particular. Furthermore, although parenthood reduces offending more strongly than marriage, the "full family package" brings the most benefit. Female offending patterns were not significantly influenced by marital status or motherhood.