Il gatto mammone (1975)

Lando Buzzanca plays a man desperate to father a male heir. However, his wife (Roseanne Podesta) is apparently barren. They decide to use a surrogate mother, which, since this was in the days before artificial insemination, means Buzzanca will have to impregnate the surrogate the "old-fashioned" way. After a mishap involving a VERY unattractive but fertile widow, Buzzanca sets his sights on young girl (Gloria Guida) at an orphanage for unwed mothers (who has already given an illegitimate child up for adoption). They hire her as a maid, but she is under the impression they're going to adopt her, leading to some quasi-incestual misunderstandings...