ABSTRACT
This chapter draws attention to the significance of Kaplan et al'. s efforts to introduce themes associated with evolutionary biology when they theorize about men's fertility and parental investment patterns. Kaplan found that having siblings close in age was associated with lower levels of fathers' time investment. This finding is consistent with fathers from the first wave of the National Survey of Families and Households (NSFH). Having other kids around presumably limits fathers' opportunities or need to spend time with their children, particularly because the major form of paternal involvement, defined in its narrow sense, involves play. The analysis that policymakers are likely to be most interested in involves fathers' reported financial contributions to their children. One appealing feature of this set of analyses is that the researchers estimate separate models for fathers' investment in their minor children as well as in their older children.
