In a mililiter of semen, there are anywhere from 20 million to 100 million little swimmers. Only 2,000 of those will make the journey.
While it only takes "one to do the trick", that's only after the egg's membrane has been beaten into submission but several hundred others.
It is really fascinating to see them under a microscope. Some will swim in circles like they're drunk, others are shaped funny and then there's those champs that just wanna hit it.
Physically fit has absolutely NOTHING to do with motility and count. Motility is the action of sperm that shows if it's got the right stuff. A low count usually includes this as doctors don't count the circle swimmers and oddly shaped ones. A man can have a high count and low motility. He can be a world-class vegetarian athlete and not be able to hit the side of a barn with a well-aimed ejaculate. On the other hand, that beer-swigging, chain smoking overweight couch potato might be carrying a few million mini-studs.
(ah, the things we learn with 10 years of fertility treatments)
