Githyanki lay eggs - they don't give birth live like most mammals. Which means Githyanki have a Cloaca. A Cloaca is an orifice which is used by a bird or lizard for defecation, sex and egg laying.
So I'd pass on that Githyanki sex...lol...ewwwwwwwwww
They also have tits, so maybe it isn't so straightforward.
This reminds me of all the conversations I had in grade school about what possible biological niches Pokemon could occupy exactly.
