How common are identical twins?

I've never had identical twins in any Sims game, but that I created them, myself. If you think about it identical twins in reality are VERY rare. Most are fraternal twins (Olsen twins, for example) who just look very muck alike, as some siblings do. I was gob-smacked to learn they weren't identical. I may have to start the family of one of my Sims in CAS. Up until recently, I could change out a Sim in CAS and still change their relationship to the rest of the family using the cheat method. Tried to do it a couple of weeks or so ago, and found out I was barred from editing an already created Sim. :open_mouth: This was game-CRUSHING to me. I don't always rely on game genetics. Sometimes I create a Sim to look the way I wish them to and then insert them into the family, later. It's just not always feasible to reshape the already born ingame Sim to look like the one you created, first. Or, maybe I just lack the CAS skill to do it. I'll give it another go, just in case I did something wrong that other day.