I'll never hear "Billionaire, genius, playboy, philanthropist" without cringe. It WOULD be in character for a 20-30 something Tony to decide that and genius made being a sperm donor PHILANTHROPY. After all, being a "playboy" wasn't conducive to marriage and family life, And eugenics -- divorced from racism -- could benefit humanity. (The school newspapers of top-ranked universities carry ads soliciting sperm donors with good family health histories.) So perhaps Peter's mother was NOT unfaithful, but wanted children and was married to an infertile man, of one whose family had genetic diseases.