Can a virgin get pregnant?

Ok. my little sister is a virgin and her and her bf were playing around (anal). somehow she felt something wet and told him he backed up and seen semen, if he didnt nut could she still be pregnant? they were standing up by the way & after he pulled out, she whiped herself in the bathroom. Theres no way she cld be pregnant right? shes a virgin. think about it, how will she be able to give birth?