My male child was not circumscribed, due to it being unnecessary surgery. everyone I know well enough to have talked about it, same decision was made. The only argument left, in this area, at that time, were a few parents who felt the baby should be cut so he would "look like his dad" . This never seemed to be a very good argument then, and doesnt seem any better now. It has become uncommon enough that the "look different than the other boys in the locker room" might now be more of an argument of why to not have it done than to do it. Nobody was making any medical arguments about it, not in any serious way, in my time of parenthood.
Maybe you could tell her it is fine if she does it herself...... no matter how it sounds to her now, I cant imagine a woman taking the knife to her newborn herself once the baby was in her arms.