When getting pregnant you only need a little bit of sperm in the vagina for the woman to get pregnant.
It only takes one sperm to fertilize the woman's egg and get her pregnant.
During sex the average man ejaculates and releases nearly 100 million sperm into the woman's vagina but only one of those sperms fertilize the egg.
Also the mans sperm must survive long enough to reach the woman's egg and fertilize the woman's egg.
Some woman have gotten pregnant by inserting a tiny bit of sperm into their vagina through use of a turkey baster.
A friend of mine did that same thing.
She took her boyfriends sperm and used a turkey baster to get pregnant and it worked.