Fallacy of equivocation or fundamental issue?

I think the issue I have with the idea of Living Unrelated Renal Donation (LURD) lies in potential perversion by making donation economic at all. My question for the authors of these articles would surround if buying and selling organs would create this corruption of the act of donating said organs in the first place. I understand the implications that the desired market is greater than altruistic donation allows for, but does that morally permit introducing an economic system to organ donation? The argument that there are a lot of benefits from introducing this kind of economic system seem to have Utilitarian ‘good for all’ bases and I think there is something lacking in terms of autonomy, or the importance placed onto a person’s physical body. Does the importance and autonomy of a person even extend to their physical body? If it does, why would it be any less significant to donate a kidney or liver, rather than to have sexual intercourse or commit suicide? Or am I committing the equivocation fallacy? I do think they attempt to defend the position of uninformed consent well. However I take issue with something potentially more fundamentally up for debate.