This study explores the change of married women’s sex preference for children in Taiwan since 1990, finding that there was a substantial decline of son preference and rise of “gender indifference”, defined as feeling indifferent about children’s sex (as opposed to desiring an equal number of boys and girls, in which the sex of children is still a primary consideration). Results show that at the individual level female education was the strongest predictor for the preference; education was negatively associated with son preference and positively with gender indifference. Cohort difference was noticeable as well. Younger cohorts were better educated than older ones hence they were more neutral about the sex and less adherent to the traditional male preference. In addition from 1992 to 2002 there was a universal intra cohort movement toward gender neutrality and away from son preference. When the younger cohorts gradually replaced the older ones as the main child bearers in Taiwanese society, at the aggregate level son preference declined and gender indifference rose.