Er, no. Tuvok and Neelix could be described as the "parents" of Tuvix, but he is the vessel that contains them, and he is in possession of the body that contains them. Indeed, Tuvok and Neelix only exist theoretically so long as they are inside Tuvix. As with a woman carrying a child, it is her choice to entertain the risk, to sacrifice herself for that child. This one life vs. two lives is a distraction.