Symbolic Incest

I want to officially retract a claim I made last week about the moral blandness of questions around IVF. No sooner had I made the claim than a senior thesis writer had us considering what one philosopher calls "symbolic incest." In Britain, cases of IVF must pass an ethics board. There have been cases in which a single woman with certain types of fertility issues wants to become pregnant through in vitro means and wants the child to be genetically related to her. So, she enlists a brother to provide the sperm while an unrelated donor provides the egg. The zygote would then be implanted and she would give birth. Apparently, in deciding whether to approve the procedure, the board considers the role of the sperm donor in the child's life -- but not in the way you'd expect. If the sperm donor wants to be involved in the child's life as a father, the procedure is not allowed. But if the sperm donor wants merely to be an uncle figure, then it is fine. To have a brother and sister act as mother and father is tantamount to incest, they argue, "symbolic incest" one philosopher labeled it, even if there is no intercourse and even if the implantation would be acceptable under other circumstances. Granted, the arrangement is odd, but is it problematic?