On the question of life
Such have been the legal and scientific mechanisms used to determine a legal equivalence to the religious concept of "The Sanctity of Human Life." But they are imperfect at best, as shown by their inapplicability to the unborn.
Indeed a legal determination, based upon reason or logic alone, likely cannot be made to satisfy the requirements for the protection and sanctification of life "from womb to tomb."
For such a decision to be reached requires that a universal assumption be made that human life is "sacred" (in a legal sense, wholly protected) by simple virtue of the fact that it is human life. As a result of the limits of logic and reason to provable notions, such a statement would need to be deemed true a priori, simply because it is, without explanation.
One may argue that such unilateral pronouncements lie more appropriately in the realm of papal or rabbinical rule, and that our system of government does not take part in the practice of religious proclamation. But recall the original universal proclamation that granted to this nation its original moral compass - we hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.
One would be hard-pressed to pare down this sentence to a logical argument with an outcome of relative certitude that life, liberty, and the pursuit of happiness are unalienable rights, whether endowed by the Creator or not. But such a declarative statements remains a central pillar of our legal system, and lies at the center of the application of ethics and morals to legal determinations.
For the issue of life prior to birth to be finally settled in the legal system, it is my opinion that, first, a similar universal declaration of self-evident truth would need to be made on life. That is, that human life, (in the form of the sum whole of an individual organism, whether 5 cells or 5 billion) is sacred and protected.
Such a constitutional amendment is unlikely, however, and thus the question of abortion rights is likely never to be settled.
From "On Science"
When does human life begin?
The story of when human life begins has a checkered past. Centuries before people knew of sperm and eggs, Aristotle argued that the fusion creating a new person did not exist until "quickening," the first noticeable movements in a woman's womb. He reckoned quickening occurred 40 days into pregnancy (18-20 weeks is the actual time). The 40-day rule was picked up by Jewish and Muslim religions. In 1591, Pope Gregory XIV supported this view of delayed animation and ensoulment.
The Catholic Church did not reach its current conclusion that life begins at fertilization until 1896, when Pope Pius IX condemned abortion at any age after the moment of conception. Many Jewish theologians now argue that life begins seven days into pregnancy, with implantation of the embryo.
Gene transcription of male-contributed genes starts even later (well after stem cells are harvested), and many scientists feel human individuality cannot be said to begin until then, when the embryo starts to actually use the genes contributed by fertilization.
The United States Supreme Court takes the position that human life begins much later, when the fetus becomes capable of independent life if separated from the mother—roughly the third trimester.
Early this month researchers at the University of Pennsylvania reported suprising findings that could profoundly alter our views of when human life begins. Indeed, if these results, obtained in cultures of mouse cells, can be repeated in human cells, theologians may have to reconsider their ideas about the very nature of life.
The researchers were raising dense cultures of mouse embryonic stem cells for research. Scientists are particularly interested in embryonic stem cells because each one of them has the potential to develop into any cell of an adult individual. In a routine screening, the researchers treated the mouse cells with a fluorescent "marker" protein they had developed to test for early-stage eggs and sperm. The marker protein sticks specifically to the surfaces of eggs and sperm, but not to any other kind of cell. Because these stem cell cultures were not eggs or sperm, the screening should have had negative results.
Surprisingly, in a culture of stem cells that had been maintained 8 days, the marker protein did stick. Over 40% of the cells glowed green, showing the fluorescent protein marker had stuck to them.
Were these egg cells? Studying them more closely, the researchers learned that groups of the cells had begun to produce estradiol, a hormone that converts to the female hormone estrogen. After 16 days, the oocyte-like cells began producing tell-tail proteins typical of meiosis, the special form of cell division that sperm and egg cells undergo. The observations were tantalizing: many of the embryonic stem cells seem to have spontaneously developed over a few weeks many of the characteristics of egg cells (oocytes).
Are they really egg cells? To be sure, the researchers will need to demonstrate that the "oocyte-like" cells can be fertilized and produce viable offspring. Until those experiments are completed, the case that they are eggs is incomplete, although strong.
The researchers continued to observe the aging cell culture, and their perseverance was rewarded with a result that may fundamentally alter how we look at stem cell research. After 40 days, the groups of oocyte-like cells in the aging culture formed what appear to be early embryos!
Examining these early embryos, the researchers found that their cells were manufacturing the sorts of proteins one would expect of normal 16-cell embryos. A few of the embryos in the culture went on to form complex balls of cells resembling blastocysts, the early-stage embryos from which embryonic stem cells are harvested.
What is going on here? These egg cells were never fertilized -- how could they develop into embryos?
Biologists have long recognized that in insects, many fish and some reptiles, adults develop from unfertilized eggs, a process called parthogenesis. That seems to be what is going on here. Normal mouse egg cells can be induced to form embryos parthenogenetically, but despite many attempts to implant them in a womb, none have ever survived to birth.
While there is no guarantee that what happens in mice will happen in humans, there seems a very good chance that similar results will be obtained in human embryonic stem cell cultures, which leads to a very interesting question. What is the ethical status of human embryos created from embryonic stem cells without fertilization?
The very possibility of human embryos produced without fertilization must have some theologians reconsidering their ideas about the nature of life as something that starts at conception with the union of egg and sperm. One thing seems sure. The controversies raised by stem cell research will continue.