Question: what happens when a man has a vasectomy?
Answer: How it works. A vasectomy works by stopping sperm getting into a man's semen, the fluid that he ejaculates. The tubes that carry sperm from a man's testicles to the penis are cut, blocked or sealed with heat. This means that when a man ejaculates, the semen has no sperm in it and a woman's egg can't be fertilised.