As I often try to argue, the idea that there is some clear line over which an egg/sperm becomes a distinct individual, making it obvious that it should be considered a full human being just like all other humans is basically nonsense.
One of the clearest problems with that idea is parthogenesis: essentially virgin births (eggs simply developing into an individual rather than needed to be fertilized). Common in many other species (though in a large number of different ways in underlying genetic mechanics), parthogenesis is unlikely in most larger mammals mostly because the mechanisms to make it happen don’t exist in us. But as a technical problem, there is no mystical barrier preventing it from happening, and almost certainly it will be possible to make happen by artificial means. While current techniques create a whole host of genetic and developmental problems, there is likewise no good reason why these hurdles cannot be overcome as we better understand the mechanics involved.
Even without doing so, however, scientists are right now trying to develop techniques to harvest stem cells from these “parthenotes.”
http://news.bbc.co.uk/2/hi/science/nature/4228992.stm
My question is this: are THESE sorts of stem cells objectionable to pro-life people? Apparently from the article, many activists have already decided that they are. The problem is, parthenotes, especially when they are never induced or allowed to grow into fetuses (with current sloppy techniques, it’s unlikely that many of them even COULD make it to that stage, and it would certainly be wrong to intentionally make someone be born with a predictable abnormality, especially one that would likely lead to an early death), seem to be a huge problem for the arguments pro-life people conventionally make against embryonic stem cell research.
Namely, there is no “distinct individual” moment that comes from the union of sperm and egg. Human egg cells have a FULL complement of DNA: it’s just that normally half of it is jettisoned, replaced by the sperm’s half as egg cell begins to divide and develop. Given that all that is required to make egg cells develop into full human beings are some physical and chemical signals that trigger particular functions in the egg cell, it seems that either the logic of pro-life activists should be that unfertilized eggs are essentially “dormant” people deserving of full protection of the law (mestruration is murder!) or their logic breaks down entirely (as I think it does anyway).
After all, they have the full complement of DNA describing how to construct what will be a distinct individual, and all that is required is the right signals and environment to make it happen (you might argue that the “electrical shock” or other artificial modifications are what somehow turns the egg into a person, but this response seems disingenuous given how much fuss pro-life people usually make over the DNA and cell alone). After all, embryos will not naturally develop unless they are given the correct chemical signals that come from a successful implantation in the mother’s tissue, so you could just as well argue that if minor changes are what makes something human, implantation is when they are “complete” not fertilization).
Maybe that’s why they have to be so vocally against embryonic stem cell research: not because they seriously think that a blob of DNA with no nervous system deserves rights or that killing it is really murder, but rather because too much knowledge about these areas of life basically clouds and messes up all their careful, simplistic arguments about life starting as a bright line right at conception or “embryo just being what a human being looks like at that point in life.” So instead, we get all this “franken-science” stuff to scare people off of thinking about it too much.
P.S.: Which is not to say, at all, that there aren’t VERY serious ethical concerns involved with genetic research and manipulation: whether it be humans or other creatures. There are many dangers (creating new diseases accidentally, causing creatures to develop and be born with horrid physical and functional defects, a whole host of social issues, etc). It’s just that I don’t think manhandling or even killing a cell in a test tube is one of them, whether it has human DNA or not.