I’m probably the last person to realize that the word sex, meaning copulation, originally came from sex, meaning man and woman.

A euphemism for copulation was “the sex act,” the act that fundamentally expressed the sexes as sexes. From that we get sex, sexual, and sexy. Nowadays we mostly talk about the genders instead of the sexes, so to get the full effect you need to replace sex words with gender words. “That’s one gendered lady.” “I have a pretty active gender life.” “homo-genderal gender.”

Sex and sexes are fundamentally related. The sex act is the act of the sexes. It’s one of those obvious truths that are obscure because they are almost too obvious.