The fertility of Muslims, which was about 10 per cent higher than that of Hindus before independence, is now nearly 30 per cent higher than the Hindu rate, and the difference according to religion is larger than the difference between the forward and depressed Hindu castes and tribes. While the lower level of contraceptive use among Muslims is the most important factor responsible for the fertility differentials, the use of contraceptives has increased faster among the Muslims in recent times. What could be the possible reasons for the residual effect of religion on fertility and caste on fertility and causes for these disparities in social and economic conditions ?