What point are you trying to make? I'm really not sure. Completely ignoring the "Moral argument" seems obviously the correct thing to do, so I have to assume I'm misinterpreting what you mean by the moral argument.
nope, i'm just asking why you think that the moral argument should be ignored, and why that position is obvious. we're talking about a group of humans and what laws and regulations will apply to their lives, likely radically changing them. these decisions will affect their relatives, who may or may not be in similar positions themselves. when legislating about persons, it seems there is always some relevance as to how the laws will affect those people's lives, even if broader considerations (value to us/cost to us as a country) are also relevant.
to be ...
As Multiheaded added, "Personal is Political" stuff like gender relations, etc also may belong here.