We investigate the effect of parents' sex composition preferences on intentions for a third child in India. Parents' preference for sex composition are balanced or mixed gender (a son and a daughter) or gender biased, commonly for a son, and are expected to change over time. Pooled sample of 22,290 couples with two children from the National Family Health Surveys (NFHS), conducted in 2005/6 and 2015/16 is used to analyze couples' sex composition preferences and its effect on third child intentions. Our results show that desire for a son dominates the preference for balanced sex composition over the ten-year period, as couples with two daughters are 7 to 9 times more likely to intend to have a third child. This intention for third child is moderated by women's education and media exposure. Parental preference for a male child continues to be a significant driver for couples exceeding the two children norm in India. Policies promoting women's education will have spillover effects on fertility intentions but would not fully close the gap caused by preference for son. Purposeful policy efforts for changing these preferences need to work synchronously with the broader efforts to address gender inequality.