The Supreme Court's decision in Roe v. Wade has been much maligned by both sides of the abortion debate throughout the 40 years since it was issued on January 22, 1973. It has been called a “non-decision”, a “cop-out”, “political weaseling” and much worse. It is commonly noted by judges that a good decision is one that both parties complain about, but if that were the only reason for the decision, it would indeed be a cynical and political one. But I think the decision is a good one, not because its middle ground is politically balanced, but because the middle ground accurately reflects the complex realities of the situation much better than the ideological extremes of either side.
The legal objections are easiest to dismiss. It has been described as “nine men in robes making a decision for the rest of us”. But this is 180 degrees from the truth. The court did not “make the decision” for everyone; they did exactly the opposite: they said that the Texas legislature, despite being a group even larger than the court and directly elected by the people of that state, cannot make the decision for every woman in Texas. They ruled that Norma McCorvey, and you and I (at least those of capable of becoming pregnant) had the right to decide for ourselves.
Some legal critics claim that the court usurped the power to create a right that wasn't granted by the constitution. They're also wrong. It's right there in amendment nine of the Bill of Rights: “The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.” The folks who wrote the bill of rights knew full well that if they started writing down what they thought basic human rights were, some power-hungry idiot would later come along and say “Look, they didn't write down X, so X must not be a basic right.” So they wrote amendment nine just to make it clear: just because the framers didn't think of it while writing them down the first time, that doesn't mean it doesn't exist. They didn't write down the right to travel and live wherever you choose, the right to educate your children, the right to marry whoever you choose, and dozens of others we would all agree are basic, fundamental human rights. But it's the court's job to enforce all of those nonetheless. The only power usurped here was by the Texas legislature, who thought they had the power to force Norma McCorvey to carry her pregnancy to term; the court told them that her rights mattered, even if they weren't among the ones first written down in 1791.
The decision itself boiled down to this: in the first trimester of pregnancy, the mother's rights are absolute and no legislature or court can limit her right to decide for herself. In the third trimester, the state may grant rights to the unborn, up to and including an outright ban on abortions. In the middle, the state can regulate to a lesser degree. As wishy-washy as that sounds, it turns out to be quite prescient in light of what we have learned in the years since.
The issue is a classic conflict of rights. When do we as a society recognize the rights of a child as distinct from the rights of the mother? There is no question in our society that once a child has been born, the umbilical is cut and its lungs are full of air, killing that child is seen as a despicable crime. There have been societies where that was not the case: infanticide was tolerated and even common in some cultures, but not here. Our culture, unlike many, even assigns gender to infants: we call them little boys and little girls from the moment of their birth, while most cultures only separate men and women after puberty, treating all children as just “children”. Our attitudes are more in line with the biology. The qualities that we admire, even revere, about people that make us revile harming them are as evident in an infant as an adult: people think, and feel, and dream, and laugh, and love, and want; infants do as well. Infant boys and infant girls have different skills and different personalities that can be observed and measured right from birth. Infants do not have quite the developed minds of adults (indeed, some parts of the brain are not fully developed until the late teens) nor are they able to express themselves as well as adults, but they clearly are selves, thinking and feeling people. In the past people have asserted that infants didn't feel pain, or never remembered events from their infancy, but we now know these beliefs are false. Infants do feel pain and joy much as adults do, and their adult lives are affected by events in infancy and by experiences before their birth, even if they don't have conscious memories of them.
The third-trimester rules of Roe acknowledge this simple biological fact: there is little fundamental difference in kind between a child just before and just after birth. A child born in week 35 of pregnancy has a 90% chance of survival. Some have survived birth as early as 24 weeks with considerable assistance from modern medical technology. We clearly think of these children as people in every important legal and ethical sense. They have thoughts and feelings and experiences, and the thought of ending their lives bothers us. There is a person there, and it is reasonable for a state to step in and protect that person from harm. Whether that person is in a womb or an incubator doesn't much affect that evaluation.
The earlier stages of pregnancy are very different. Let's first of all dispose of the idea of “conception”, which is a religious idea that doesn't have any real biological meaning. The biology of human development begins with fertilization, which can't really be called an “event” because it is a complicated process in many stages that can be accomplished in different ways. But for the moment I'll concede the point and say that a zygote exists after fertilization. Once the DNA from the egg and sperm have combined, the newly-formed zygote then begins to divide into two cells, four, eight, and so on. At this point there aren't yet any specialized cells: they're all stem cells, and will only take on specialized roles as organs, nerves, and so on much later in the process of development (if they continue at all—many of them will just die off).
The process of development itself can take many turns. The majority of the time, in fact, the process results in nothing at all. Most fertilizations are simply flushed out with the mother's next menstruation and never develop. The woman never knows that any fertilization occurred at all. In those fewer cases where the zygote does make it through the tubes to implant in the uterus, its fate is still undetermined. It might develop into a person, or two people, or three, or half. Identical twins, for example, result when the multi-celled zygote splits at some point, and both portions go on to implant and develop into fully formed unique people (albeit with identical DNA). Identical triplets are quite rare, but also possible. Another even rarer possibility is that two different zygotes will merge at some point in their development and develop into a single fully-formed person with two sets of DNA. These are called tetragametic chimeras, and are often born with defects, but can also be born as perfectly normal infants who may not even know that they were the product of two different fertilizations.
This is where the “life begins at conception” argument falls down. Yes, a zygote after (and arguably before) fertilization is living, in the same sense that any of our skin cells or liver cells is living. They can divide and grow and contain a full set of genetic material. We can now grow skin and muscle tissue in a dish from a single cell. But the relevant question is not whether the thing is living or not, or even whether it is human. The question is “is it a person?”, in the sense of laws that make harming people an act of violence we detest, or is it merely a collection of cells like the skin cells we flush down the drain when we wash our hands, or blood cells that we donate to the Red Cross? What is it about people that makes them specially deserving of protection? A good way to answer that is to think of the twin case: why do we consider twins to be two people, not one? It's simple: each twin thinks and feels and dreams independently. Each has its own personality and its own desires and fears. It is untenable to argue that the single zygote that would later develop into these two people had any of those qualities. It had no brain, no nerves, no eyes, no ears. It had only the potential for developing those things—and we didn't know then from the zygote stage exactly what it might develop into. It might have become a person, or two, or half, or it might not.
Likewise, there is nothing special about the type of cell that is the zygote. We retain stem cells even into adulthood, and any of them also has the potential to develop into any other kind of cell. The day is not far off—if it hasn't happened already—when a single cell from an adult human will be able to produce a cloned person, just as Dolly the sheep was created from a mammary cell of her mother. Clearly, it would be morally repugnant not to grant that person the same legal rights as other people, because she will have the same thoughts and feelings as any other infant, despite the fact that she was not the product of fertilization at all. Whether or not you approve of cloning, the fact is that it demonstrates vividly the fact that the concept of one-fertilization-one-person doesn't hold water.
So the first trimester rules of Roe also reflect what we know about biology: a few cells don't make a person, and it doesn't make sense to arbitrarily grant them the rights of a person when we don't even yet know what they may develop into. The mother, on the other hand, is quite clearly a person, and her rights can and should be protected. Laws against birth control, “morning after” pills, and yes, even first-trimester abortion clearly do victimize real women, and we simply can't legally or ethically justify that to protect what is clearly not a person.
Lastly, there's the middle ground: the second trimester. The justices here make another wise statement: we don't know. At this point in the development of what is now a fetus, it begins to resemble a person. Twins have already split, chimeras have already joined, and it begins to develop eyes and ears. Sex differences start to develop. We all begin as female. At some point in the growth process, those with Y chromosomes will produce hormones that cause male characteristics to develop, unless the fetus has AIS. At 18 weeks it responds to loud noises. At 22 weeks it has a normal sleeping and waking rhythm. It might have the beginnings of something like thoughts and feelings, or it might not—we just don't know. And because we don't know, the justices leave the issue for further debate by the people's representatives.
In short, the justices in Roe weighed the legal and biological facts before them, and reached the right decision, despite the fact that they had to decide decades before some of the biology I mention above was known, and despite the fact that they knew their decision would be disliked by both sides of the political debate on the issue. I for one find that remarkable and worthy of praise.