Male and female reproductive systems allow human reproduction. Fertilisation occurs when a sperm and egg join to form an embryo. An embryo develops into an unborn baby in the uterus during pregnancy.

One such phenomenon is the sperm's ability to survive in the female reproductive tract during estrus, even though oviductal immunity is heightened during this period, making the tract more hostile ...

A study found that both men and women with greater upper body strength reported having more sexual partners, defying ...