So far there are 2 females, 2 males and one intersex monsters. So it's perfectly balanced. I could do variants of each monsters but that'd be more work for less variety, when I could just add other monsters.
If I have time I'll do it, but so far it's already 50/50 and there's nothing I can do about it alone.
As for a toggle that's a huge no from me. Sexualities and genders can't be erased with a button, and you can spend more time with the characters of your choice in the current level.
Plus I genuinely spent more time working on the M/M sex.