What I got from the new patch (besides unisex hairs and clothes, which are just that: "new" hairs and clothes):
- You can
create a male sim who can get pregnant, or a female sim who can impregnate others. Or a sim who cannot reproduce at all.
- Any of the gender customization options beyond clothes and hair are accessible only from CAS or entering CAS through cheats.
- No sims will spawn with these new options. You'll only get born in-game and generated sims who are typical females and males.
- The reproductive options are the only ones that would have a real, tangible effect on the game. Stuff like feminine vs. masculine body shape, default clothing preference (that you can override just by setting your filters differently), and whether they stand up to pee or not is cosmetic at most.
Personal Opinion, Not an Official Ruling Yet: I don't care what options you give your founder, because I don't see a huge advantage that would arise from having a male founder who could get pregnant/a female founder who could impregnate. But you're stuck with the rest of your sims having the usual options, because as of right now, there is no dynasty-legal way to change them.
Oh, and creating a sim who can't reproduce at all is fine, but it does fail your dynasty before you even start.