Settle the dispute with the strong, simple argument. Sweep up all the edge cases and put them in place.
Anything with a Y chromosome is male, period. IDGAF about genitals. Y = male. No Y = female. Couldn't be simpler.
Oh, and shame the tranny for using someone's real health problems as an excuse to parade their own public perversion. If I was XXY, I'd be FURIOUS at trannies.
It fails as a hard binary.