I'd just wish to point out, as many have before, but reading your comment makes me think you missed it, that SD cut the females out only, and only because they wanted to have great amount of detailed customization.
They couldn't just throw one female there and leave it at that. They wanted to do it properly. If they added females they would've had to create a duplicate of every single garment in the game, so that the females can have as much customization. Partly it was a question of the long time it would require, but the other major reason was that there was simply not enough capacity in the engine to do it.
From what you've said it sounds like you don't understand that the customization for both genders would've been cut in half if females had been fully added.
And whether you recognize this or not doesn't really bother me, but I hope you wouldn't say SD did the decision of leaving out females for "stereotyping and stigmas attached to having female game models" because that is complete and utter nonsense and I have no idea where you got that idea.
It is not that I miss the reason given, but rather that I see more depth to the reason.
With three types they could just put one female in instead of a male and leave it at that and would not need to change/duplicate anything if they simply made it a "unisix" option, because in game there needs to be very little difference between males and females, simply having the difference exist. Sure some might see that as a lack of customization, but the male/female choice doubles the options to begin with.
And it is due to the stereotyping and stigmas attached to the models in gaming. I'm not saying that SD is stereotyping or placing stigmas on them, but that they exist and change the precieved requirements. There's a belief that for it to be an acceptable female character model it requires a collection of differences for it to work, the majority of which don't actually need to be there.
Take a look at female character models in games like Goldeneye, Perfect Dark, Metroid etc. There's very little needed to define them as female. Then you look at other games like Soul Calibre, Tomb Raider, etc. There are some substantially more notable differences there. In either of the cases the charcacters are still recognized as women.
In short, what it means to be a "female character model" is being over thought, at least for the purposes of inclusion. In the long run more detail will always be welcome, but a foot in the door is still "in the door".