Okay, here's a poser. What about all the eggs—potential human beings—that a woman produces in her childbearing years (about ~500 maybe) that are just eliminated every 28 days? If one were to carry some ideas to the extreme, doesn't a woman have a moral obligation to get pregnant as often as possible in order to bring all those potential human beings into existence? [There are some male chauinist piggies, often of a religious bent, who think so!]

Here's a possibility, and there is a precedent for this:   If a minor dies in an accident, his or her parents can give permission for the minor's organs to be used for transplants. Why not let the couple involved decide what is to be done with the unused eggs?

Don Firth