If only this gelled with Gus Van Sant's Psycho do-over. 533 kids discover their father was Norman Bates. Follow some of his off-spring as they see what growing up in a single-parent environment did to their father's psyche and their growing concerns if his obsessions with Mother are genetic.
Alas Delivery Man is intended as a sperm donor comedy, and Vince Vaughn vehicle rolled into one.
My idea is better.