 First, we should note that this area is subject to the implications of the Non-Identity Problem (Parfit 1984). In particular, given that (let’s assume) many paid sperm donors would not have donated but for the money, it is plausible to supposed that children who suffer psychological harm when they find out about their donors would not have existed if there hadn’t been payments. Therefore, for standard reasons relating to the Non-identity Problem, they may not be harmed by the practice of payment—or at least not in the usual comparative harm-to-interests sense (worse off than they would otherwise have been). (See the entry on the  non-identity problem.)  So, while there may still be a child welfare argument against payment, it must rely not on harm-avoidance but rather on impersonal welfare considerations.