Added to the ever-growing pile of evidence that Trek writers can’t do science.
Well, if you take sexual to mean they are of two sexes, they aren’t wrong. I mean you could call them bi-gendered I guess, but since he’s talking about their biological sex and not their gender identity…
technically Bones is correct. these terms are often taken from science. take asexual, for example. While it has come to mean a person with no sexual drive or desire, it was originally solely a scientific term meaning “without sex”: “A” and “sexual”.