I was really thinking about someone who had the surgery a while in the past, long before even contemplating conversion. What about a situation like somebody who had considered him or herself Jewish and then found out they weren't (because of matrilineal descent) and wanted to be sure of being considered Jewish by others.

There isn't any particular case I am thinking of. It's just that I've seen so much in the Jewish press about somewhat liberalizing attitudes towards homosexuality that I started to ponder this question.