The dramatic increase in nonmarital fertility in the United States has generally been explained in terms of either economic circumstances or changing norms and values. We believe that fertility motivations, and the intentions they generate, should be taken into account, and we hypothesize that nonmarital fertility is more likely when children are seen as an important source of social capital. Using data from the first two waves of the National Survey of Families and Households (N= 1,155), we find support for these views. Women who considered the social resource value of children to be high were more likely to have an out-of-wedlock birth than were those who did not. Women who did not intend to have a child were less likely to have a nonmarital conception than were women who did intend to have a child. We conclude that understanding recent increases in nonmarital fertility requires an appreciation of the social benefits that children bring to their mothers, married or not.