Several states in northern Nigeria, which is mainly Muslim, had said they would start to impose the full panoply of sharia law on all Muslims, with floggings for sex outside marriage, amputations for other crimes, a ban on prostitution and the segregation of men and women in public.

ECONOMIST: Nigeria falls apart again?

The arguments against single-sex education come primarily from civil-rights and women's groups who oppose publicly-funded segregation on principle.

ECONOMIST: An idea that may be worth trying