The key (reproducing_organ) only has 2 (or 3) values. If you want a composite key (reproducing_organ, sexual_preference, sexual_identification), you would get (at most) 3 * 3 * 2 (?) possible values. If you want to expand that key to include X because PC reasons, I'm not listening anymore.

> What is it you think individuals in this group have in common?

Penises and vaginas. Since those with ambiguous genitalia are a rounding error, they can flip a coin.

Are you serious?