While the fascination with the permutations of an individual is understandable, I think it is more profitable to "look" at the person in the context of their social "field." Bowen has described the basic social triangle as two individuals feeling emotionally close and intimately bonded (mother and neonate) while the father would be in the outside position in this basic nuclear triangle. Fathers cannot breastfeed. This wider view reveals a host of new opportunities for research.
On the topic of homosexuality, I have long wondered about the possibility that during pregnancy when the mother's blood stream is flooded with many powerful hormones in different combinations and at different times during gestation if it were possible that a flood of estrogenic (female) hormones at a particular critical moment in the devolopment of a male fetus would/could cause a subtle yet powerful repercussion in the later sexual devlopment of the child, esp. at puberty. Now, also, this child would be at a particular vulnerability if the mother had an unconscious or even conscious desire to have a daughter instead of a son. You can see where I'm going here. The obverse situation could also, of course, be so.