This study investigates the effect of childbearing on parental involvement in stepfamilies and intact families, based on the reports of 1,905 stepparents and biological parents from the National Survey of Families and Households. Regression analysis indicates that involvement with children declines over time, especially among respondents with only stepchildren in the household. Respondents who have had a child between waves of the survey reduce parental involvement at a slower rate than respondents who did not have a child. These effects are explained by the children's age. The birth of a child has a similar effect on parental involvement in stepfamilies and intact families. These findings suggest that the addition of a half-sibling is not particularly beneficial to stepchildren and provides further evidence that couples with children from prior relationships should not make the decision to reproduce to cement stepfamily bonds.