Some countries/cultures do this barbaric thing where they take a girl, around eight, and cut her up on the inside, then sew her up so the sides heal together. This way her husband both knows she's a virgin, and has the pleasure of ripping her open on their wedding night. After she gives birth, she is sometimes cut up like with a cheese grater or broken glass and sewn up again so the husband can have the pleasure again. This is a cultural thing, usually tribal in African nations, and isn't necessarily Muslim. Islam does practice female circumcision, which varies in degree, but basically knicks or scars the clitoris so that the woman cannot orgasm, making her less likely to be unfaithful. They also believe, men and women alike, that an uncircumcised woman is unclean. But the degree of female genital mutilation to which you refer isn't exclusive to Islam.
Oh, I've studied it extensively.