Hint: It’s in Africa. It is not a cult. It’s about family size.

Answer: It’s a program for adolescent mothers run by the Center for Girls Education in Zaria, Nigeria, which is expected by 2050 to overtake the US as the world’s third most populous country. Researchers have found that the program has an unusually large impact on family size in Africa because it helps the young women space out the births of their children.