At one hand we reduce everything to genes, on the other we know that this reduction has no meaning. Genes are the zero point that induce meaning, but are absolutely meaningless. Knowing who your biological parents are, your blood ties doesn’t matter and are the only thing that matters. Your child isn’t a child. It’s irreducible from the beginning to the end. Although we can’t understand why this is so.
Donors are perverts and altruistic good-hearted men. It makes sense to prefer to throw away your seed than to give it to someone who needs seed (which is quite pervert to).