How many sperm dose it take to get a woman pregnant?

One sperm, makes one child. Two make twins if both attack and dissolve the outer protein of the egg at about the same time. I would say: The chance of one sperm in the bathtub finding the one egg in your uterus is very low. Pregnancy usually requires sex with much agitation to get past the mucus plugs in the uterus and the deployment of at least 30 fighting sperm to get pregnant the first try. So one healthy sperm can do.