A new reproductive health bill that would promote the use of contraceptives and bring in mandatory sex education in the staunchly Catholic Philippines may fail because of opposition from church groups.

Supporters of the bill, currently being debated in the national Congress, say it will reduce poverty by bringing the population growth rate under control and decrease the number of sexually transmitted infections, which are on the rise.

But the Catholic church, which wields considerable social and political influence in a country where more than 80% of the population of 96 million people is …