Considering that you might otherwise be a healthy individual; low probability of genetic defects, good heritable traits, no STD's, you essentially get a free pass to be a brood parasite and pass on your lineage without having to invest in the cost of raising a child.

Depending on what country you live in, you can be compensated for your efforts, as well as free genetic and family history tests, and HIV/Hepatitis etc screenings, where normally those would cost a great deal. You have no legal rights (or obligations) to the child, which means there can be a dozen little you's running around and no obligation to pay alimony or child support. You'll have sired a child that you know for certain was chosen by their parents and not an accident, and will presumably be raised in a stable family that has been screened beforehand. You'll have sired a healthy boy and reduce the likelihood that children with genetic defects are born. Another man (or woman) will even raise your child.

And all of this is already seen as a social good, especially from a Darwinian standpoint I see no downsides to this.

What are your thoughts?