The big argument on AUTOCAT today was over the subject heading "Gay parents" vs. "Same-sex parents." There was some confusion over whether or not one authority record should have been cancelled in favor of the other (basically, "don't these mean the same thing?") or whether "Same-sex parents" should at least have a "broader topic" reference in the authority record for "Gay parents." I think it all came down to, "they are not necessarily redundant," with lots of references to films and sitcoms in which children have parent figures who are not gay but who are the same sex as one of their "actual" parents (a biological parent, or a guardian).
It kind of began to feel like a Friday thing (odd tangents, jokes, and other things that aren't really work-related are generally restricted to Fridays on AUTOCAT, although sometimes Friday starts a few days early), but similar discussions have happened in the past over other subject headings. Most often the subject headings causing confusion are religious or legal ones, where it is sometimes difficult for those without a lot of knowledge about the topics to understand how they should be applied.