There was a pair of conjoined twins on the other day who were effectively one two-headed girl. There was basically one pelvis with one torso coming out of it, but the torso sort of partly spread apart just enough to have to heads on top of it.
They were 16 so were driving, which the neurologists found fascinating. They could do everything normally. However they couldn't offer a good explanation of who controlled which limb. They just sort of managed automatically with the co-ordination etc.
They clearly had one pelvis so presumably one set of genitals and reproductive organs. I guess it didn't really matter to which twin they belonged…