When does a human embryo become a human being? For right-to-lifers the answer is unequivocal: at the moment of conception. And this idea, that a person comes into being as soon as an egg and a sperm fuse, is the platform on which Christian conservatives are building their case against stem-cell research, especially the practice of therapeutic cloning, which they consider worse even than murder. In their eyes, a person is being created only to be destroyed.
Yet therapeutic cloning is the process on which many medical researchers are pinning their hopes for a new generation of cures. This technique would enable them to generate stem cells specific to each individual, thereby achieving a perfect tissue match. The problem is that in order to get these matched stem cells, you have to create an embryo. Its the same process used to create the infamous Dolly, but in therapeutic cloning there is no intention of letting the fertilized egg develop into a mature form. Embryonic stem cells have to be culled about seven days after fertilization -- wait any longer and they begin to lose their all-important plasticity. At the seven-day mark, an embryo is a ball of just a few hundred cells known as a blastocyst; it has no viability outside a womb, and there is no differentiation of any tissue types -- no skin or bone or muscle cells. Yet right-to-lifers would accord this ball full human status. The problem is, in the process of culling stem cells, the embryo is torn apart.
The sanctity of the human person is a principle on which almost everyone agrees, but just when this entity emerges is not easy to determine. Contrary to what many abortion opponents imply, there is no historical standing to the idea that a person begins at conception -- not even in the Catholic Church. Nowhere is it written in the Scriptures that life begins in the blastocyst. Traditionally the formation of a child was understood to be a gradual process in which coming into being was associated with something called the quickening. (Today the term is still used to mean the time that a mother first feels her fetus move.) In the fourth century, no less a Catholic authority than Augustine sanctioned abortion up to 80 days after conception. Not until 1588 did Pope Sixtus forbid all abortions, and that edict was rescinded three years later by Pope Gregory XIV. The first U.S. anti-abortion laws also distinguished an early period in fetal development: In 1821, Connecticut outlawed abortion after quickening, making early-term abortion perfectly legal. By the 1860s, however, all states had passed comprehensive criminal abortion laws.
Defining conception as the moment at which a person is formed makes abortion under any circumstances an act of murder, which is clearly the status Christian fundamentalists would like it to have. Under this calculus, any medical technique that destroys an embryo would also constitute homicide -- no abortion, no therapeutic cloning, no embryonic stem-cell research (except in cases where the cells were culled from naturally miscarried fetuses). Yet, if we carry this logic through, we also have to ban in vitro fertilization.
IVF has enabled millions of infertile couples to share in the joys of parenthood, but locked away in the freezers of in vitro clinics are tens of millions of surplus embryos, the bulk of which will never be implanted. Parents of these embryos currently have three options: destroy them, donate them for research or continue to store them cryogenically. If personhood begins at conception, then the first two options will be ruled out as murderous, leaving only the third. Yet that too would constitute homicide, for cryogenic storage itself eventually kills the delicate embryonic cells.
The more science discovers about cellular mechanics, the more absurd it becomes to define a person at this level. If a single-celled fertilized egg, which is incapable of surviving on its own, is to be defined as a fully resonant human, then why not extend that status to an unfertilized egg, which is theoretically capable of parthenogenetic reproduction -- i.e, without a sperm. (This actually happens in many species of fish and among some species of lizards and birds.) Cloned embryos themselves (including the therapeutic variety) are generated from ordinary body cells such as skin and muscle cells -- in Dollys case, the progenitor cell came from an udder. In this process the DNA-rich nucleus of the ordinary cell is scooped out and transferred into an egg whose own nucleus has previously been removed. (Alternately, the entire cell is simply injected into the denucleated egg.) If this new hybrid eggcell is to be accorded human status, then why not the original cell itself? Which means that in effect every cell in your body is a full human being. Then, of course, there are sperm, each of which are just itching to fertilize an egg. The logical conclusion of this line of reasoning is onanism -- to quote Monty Python: Every sperm is sacred, every sperm is great, if a sperm is wasted, God gets quite irate.
As a former Catholic myself, I feel deeply ambivalent about abortion. Although as a feminist I believe every woman should be able to terminate an unwanted pregnancy, our goal should be to end the need for abortion. Sex education and contraception are the appropriate technologies. My intention is not to dismiss what I believe are very real concerns here but to highlight the absurdities entailed in basing medical policy on a cellular definition of human life. Moreover, if we make personhood synonymous with a single cell, then how do we define death? Presumably that must come only when every cell in a body has died, and each one of those cells presumably also has the right to be kept alive as long as possible. Given the rapidly advancing technology of life support, such a policy carried through with any degree of social equity would quickly bankrupt our entire medical system.
Margaret Wertheim is the author of The Pearly Gates of Cyberspace and Pythagoras Trousers: God, Physics and the Gender Wars, and is the Weeklys science columnist. See Quark Soup, Page 25, for her discussion of twins and cloning.