This is a really interesting question. It’s one of the only instances in which I think Marquis gets the issue wrong. In his article, he basically says that no, it wouldn’t be wrong to destroy the sperm because one can’t know which individual sperm would have gone on to fertilize the egg. Since we don’t know which sperm possesses the future of value, we can’t treat them as though they all do.
This is problematic. In my view, nothing biologically prior to the first step in embryogenesis, or conception, or the fertilized egg, should morally matter. An ovum or a sperm, by themselves, don’t possess the future of value like ours.
Notice what an adult needs in order to enjoy his or her future of value. Food and water, shelter, health, etc. A fetus needs the same. Does, say, a dog need the same in order to have a future of value like ours? No, a dog would need to undergo rapid evolution of some sort, or be transformed into a human, or to have some kind of cognitive augmentation — in other words, it needs a separate process in addition to just what an adult needs.
The force of Marquis’ argument was to see an adult’s future of value to be the same as a fetuses’ not just with respect to the value itself but with respect to what it takes to activate those futures.
An individual sperm needs something more than the elements above. A fetus, just with those elements, will become a child, then an adult, and so on. But a sperm needs an additional thing: it needs an ovum. It will not develop any further without one; a fetus, on the other hand, as an inner-developmental trajectory without recourse to needing anything over and above what a child or adult needs. What scientists used to call the inner life principle.
Otherwise, why stop at sperm? We could say the mere intention to procreate, if it is destroyed or suppressed, is robbed of a future of value. But drawing the line at conception seems meaningful to me given that that’s the very point where nothing extrinsic or additional is needed that humans don’t already require for their regular development.
Thanks for the question. It’s a good one.