(January 12, 2018 at 10:45 am)Hammy Wrote: Can't guys of any age be healthy sperm donors?
The probability goes down throughout life. In a man, sperms are produced throughout life. Each generation of sperm is made by cellular division of germ cells that were made during production of previous generation of sperm cells. So with the production of each generation of sperm, possibility of additional error is introduced into the genes carried by that generation. When a man is old, the sperm cells he produces is hundreds of cellular generations removed from the genes he inherited as an fertilized egg during his own conception, and carried with them cumulative errors from gene transcriptions over hundreds of cellular divisions.
So the older the man, the more mutations his sperms will possess and pass on.
It's probably fair to say many more mutations in the human gene pool originated with man's sperm than woman's egg, and a disproportionate number of those originated in elder men's sperm.
