Can a Female Reject Sperm?

It appears some sperm fails to 'communicate' with the female reproductive tract and while a man can appear to be fertile, his semen can be rejected by a woman if it's not compatible with her. This is more likely to happen if a woman has not previously been exposed to his sperm over a period of time.

What stops sperm from reaching the egg?

Spermicide is a kind of birth control that has chemicals that stop sperm from reaching an egg. You put it in your vagina before sex to prevent pregnancy. You don't need a prescription to get spermicide — you can buy it over-the-counter at most drugstores, pharmacies, and superstores in the condom aisle.

Does the female egg choose the sperm?

Researchers from Stockholm University and the Manchester University NHS Foundation Trust found that the egg effectively chooses the sperm it wants, and rejects the others. "Human eggs release chemicals called chemoattractants that attract sperm to unfertilised eggs.