Paul was in his 80s when someone called to say she was his daughter, conceived in a fertility clinic with his sperm. The only problem? He’d never donated any.

Harmony smiles, blinks and frowns. She can hold a conversation, tell jokes and quote Shakespeare. She’ll remember your birthday, McMullen told me, what you like to eat, and the names of your brothers and sisters. She can hold a conversation about music, movies and books. And of course, Harmony will have sex with you whenever you want.