On the basis of social structural theory and identity theory, the current study examined changes in gender-role attitudes and behavior across the first-time transition to parenthood and following the birth of a second child for experienced mothers and fathers. Data were analyzed from the ongoing longitudinal Wisconsin Study of Families and Work. Gender-role attitudes, work and family identity salience, and division of household labor were measured for 205 first-time and 198 experienced mothers and fathers across 4 time points from 5 months pregnant to 12 months postpartum. Multilevel latent growth curve analysis was used to analyze the data. In general, parents became more traditional in their gender-role attitudes and behavior following the birth of a child, women changed more than men, and first-time parents changed more than experienced parents. Findings suggest that changes in gender-role attitudes and behavior following the birth of a child may be attributed to both the process of transitioning to parenthood for the first time and that of negotiating the demands of having a new baby in the family. (Contains 3 tables and 1 figure.)