This paper draws on evolutionary life history theory to examine nonmarital births in the context of women's ability to secure male parental investment for their offspring. While nonmarital births are usually defined with respect to marital status the day of parturition, we adopt a more nuanced approach that corresponds to men's willingness to commit to family obligations. Our approach distinguishes between marriages preceding pregnancy, marriages occurring between pregnancy and birth, marriages immediately following birth, and births that are not followed by marriage to the child's father. Using retrospective marital and reproductive histories from the Panel Study of Income Dynamics (PSID), we observe a range in women's life history outcomes (fertility and marital measure) corresponding to this range in male commitment around the time of first birth. Self-selection biases are not examined in this analysis, although their implications are discussed.