My mother-in-law tells a story of a doctor she knew who would tell parents-to-be he could always predict the sex of their baby (this was before scans were so co

My mother-in-law tells a story of a doctor she knew who would tell parents-to-be he could always predict the sex of their baby (this was before scans were so common). He would tell them "boy" and would write it down on a piece of paper and put in a drawer, "so neither of us forgets". If it was a boy, they'd be very impressed. If it was a girl, they'd go back to him, he'd pull out the piece of paper to prove to them, no, he had been right. Of course on the paper he'd written "girl".