You’ve made two points here:1: Nothing is allowed to use another individual’s body without consent, and 2:The ability to survive outside another’s body is required for humanity. I’ll focus on the second point for the extent of this post. I think that what this biologist was referring to was not primarily the unborn’s location (inside or outside the body) but its dependence (whether or not it’s able to survive without another person’s body). Consider; would you grant that, if pregnancy occurred outside of the body, but with the unborn still fully dependent on the mother, that abortion would be wrong? Clearly not; it would still be dependent on her body. The relevant issue is, not the location, but the dependence. So, does dependence on another for survival negate one’s humanity? Ironically, several popular pro-choice arguments deny this. Take, for example, Judith Jarvis Thompson’s famous violinist argument. In this argument, she argued that one’s right to bodily autonomy would justify unplugging from the violinist; but she granted that the Hulk Grumpy old man I can’t go to hell the devil still has restraining order against me shirt was a human being, regardless of his dependence. Thus, as Thompson recognized, dependence on another is irrelevant to one’s humanity. This dependence might justify killing the other person; that’s a different question, but it’s blatantly obvious that neither one’s location (inside or outside the body) or one’s dependence on another for survival has anything to do with one’s humanity. Pregnancy is incredibly damaging, dangerous, and life-threatening for a woman. Trying to separate that into a “what if” is an insulting fallacy and I won’t play that game. The fetus is not a fully autonomous functioning human being. It’s a potential human being until it transitions after birth.
A woman has full regency over her body and what goes on within it.
End of story.