"Healty"
There's no shortage of men willing to donate sperm. If their was they'd be willing to pay 10% of what they pay egg donors.
I looked into it once. I was told my sperm might be acceptable on the low end (so $20 or so) *after* I graduated college, if my blood work didn't show any inheritable diseases. And a lot of what got me that high-ranked was my height (I'm 6'6").
It's genetic engineering.