In the lab, I happen to be studying embryology (in frogs as the model organism). I’m not going to blog on the theory or methodology of my research in the immediate time, but I am interested in making more general reflections. For instance…
Embryology intersects with the public sphere to generate some very hot political issues, such as embryonic stem cell research, and first-trimester abortion. The ethical question of “when does life begin” is the usual refrain. The “Pro-Life” political factions typically make the claim that life begins at conception, and that any intervention ending the embryonic development is murder. There are a lot of loaded assumptions that I’d like to dispute from the basis of my laboratory experience.
When does a life begin?
The immediate consequence of the union of an egg and a sperm is that a zygote is formed. That’s a single diploid cell, now having obtained the unique and complete genome. In a genetic sense, it is a new life of its own. For human embryos, while it still relies on the mother for the right conditions for development to continue, it is a human being of its own in this sense. The same is true for all other mammalian embryos, and similar for all other vertebrates (relying on their egg yolk instead of mother). The argument for “Life begins at conception” starts with this point – that after conception, a single cell carrying a unique genome is the moral equivalent to a fully-grown human being.
The problem with this is that (I think) most people reject being defined by their genes. A human zygote is a human being, but it is clearly not yet a “person.” It has no personality. I cannot interact with it, or bond with it. It has not been named; the mother’s body is barely aware it contains an embryo yet, the mother herself is totally unaware. It is still an “it.”
In the human embryo, the zygote has divided in rounds to become not one cell but 150-200 by day 5, and is now called a blastocyst. Manifestly, it is nothing more than a hollow ball of cells. In the coming days it will implant into the uterus, gastrulate to form the triblastic germ layers, and by day 14 it will have formed the neural tube. The formation of the neural tube represents the first hint of the central nervous system, which is the seat of consciousness, personality, and the characteristics that we recognize instinctively as being “human.” But it is still an unformed central nervous system, the mother might not yet be aware she is carrying a child, it is still an “it.”
When then does it become something of a person? Not at any one point, is all that we can definitively say. After day 14, the issue becomes more and more murky, and the embryo becomes a person. By the 6th week, brain activity is detectable and the heart begins to beat. Limb buds appear where the arms and legs will grow later, and organs begin to form. By the end of 8th week, eyes have begun to form, facial features have begun to develop, and the embryo is capable of movement. By 10 weeks, the first trimester has ended, and the embryo has become a fetus.
Sometime between day 14 and the end of the first trimester, “it” has acquired features that make it recognizable as a nascent human being. Correspondingly, even most secular people accept the curtailing of abortions after the end of the first trimester. Some religions however consider that, whatever the counter-argument, even the zygote is sacred.
How does knowledge of the sacred influence a person
I’ve always been a secularist, but I still reflect on these issues of what is “sacred” in biology. Stated simply, is even a human zygote sacred? A blastocyst (the stage at which embryos are sometimes destroyed for obtaining embryonic stem cells)? To me, no. But to someone else who would answer yes – would first-hand experience working with early-stage embryos change such a person’s mind?
I don’t have a direct answer, but as I said, I don’t think the zygote or blastocyst is an equivalent to the adult organism. Not even close. I mean, visit an embryology laboratory and look at them. It seems the height of naivety to claim them to be the equivalent.
Surely, knowledge of embryology must be the bane of this naivety.