Did you try editing her face with that plastic surgery thing from University? Maybe that'll reset her genetics?

I would try what Erry said. Guarantee she had genetics but they either changed how they worked or just deleted that part from her file.

The thing is, I think that Bella Goth is kind of a "broken" sim. She's not broken in the way that sims in Olive Spector's garden are, but she was supposed to stay dead.

Maybe it's not that she doesn't have genetics.... I am not sure, but maybe it's the way her pregnancy is linked up the what characters? That problem is usually when fathers are not correctly linked him, and cause the child to be a mom clone (Like Brandi's unborn son), but Bella seems to have it backwards...

I know that Strangetown Bella does not have this problem, but it's not like that'll fix it.

Uhm, however, I haven't heard of this problem either! You may have to go trekking in her SimPe files....