Roe v. Wade said that because nobody can really know at what moment human life begins, we are free to decide such and such. Since then, science has made vertiginous progress. I'm going to tell you how much more we know now about the beginning of the human person than we knew in 1973.
Life has a very, very long story. It has been transmitted for millennia inside the human race.
But each of us has a very precise starting moment, which is the time at which the whole necessary and sufficient genetic information is gathered inside one cell, the fertilized egg, and this moment is the moment of fertilization.
There is not the slightest doubt about that.
We know that this information is written on a kind of ribbon that we call DNA. It's a long molecule on which, under a specific code, all the qualities of the future person are defined. It measures exactly one meter in length inside the sperm, split into 23 little bits inside the chromosomes, and one meter inside the ovum; so that at the beginning of our life, we have two meters of ribbon, so to speak, on which everything is coded. To help you understand the miniaturization of these tablets of the law of life, this meter-long molecule is coiled so tightly that it fits easily on the point of a needle. Life is written in a fantastically miniaturized language.
At the time of Roe v. Wade, we knew that the information was inside the first cell, but nobody was able to read it, and nobody was able to say how it was going to express itself, so that the information would finally become a living thing telling us, "I am a man."
Today we know that life is very similar to what happens with a magnetic tape on which music has been recorded. On the tape itself there are no notes. In the tape recorder there are no musicians, no instruments. Nevertheless, because the information has been coded at the moment it was received by a microphone and then transmitted to the tape, the player/recorder can read it again and give some movement to loud speakers, so that what is reproduced for you is not the musicians, nor the notes of the score. What is transmitted to you, if you are listening to "Eine Kleine Nachtmusik," is the genius of Mozart.
In exactly the same way, the symphony of life is played. It is written in a very special code on DNA, and the first cell is the first part of the magnetic reading machine, so that it will decipher the code on DNA, and play human life. If the information that is inside the tape recorder, which is that first cell, is human information, then this being is a human being. We know that at the beginning there is a message, and this message, if it is spelled out in the human way, makes what is a human.
This notion of information is not wishful thinking. It's not a meta-physical hypothesis. It's plain science. Those who do not wish to face its implications often say that life is purely a dynamic, a movement that continues. Well, we can freeze early human embryos. As we lower the temperature, we slow down time; and when we get very deep into the freeze, time is suspended.
But the human beings that have been frozen are not dead; if we give them back a normal temperature, they will continue again. They will regain their own autonomy and begin again to be themselves. So we know that we have interrupted the dynamic, the movement; but if we have not destroyed the information, life can start again.
In 1973 we could not tell anything about the content of the first cell. If we looked at what was inside it, at the genetic message which was coded inside, we killed that cell. It was the same with the very young embryo. For the human embryo of a day, two days, a week of age, it was impossible to look at him and see whether this embryo had such-and-such a quality without destroying the embryo, because of the invasiveness of the technique.
Now an extraordinary discovery was made in 1985 and has been used in laboratories since 1987. From an embryo at three days of age who has possibly four or eight cells, we can very carefully take one of these cells, puncturing the zona pellucida with a tiny hole and removing it, then closing the hole. Then from the cell, with a new technique called PCR, that is "chain polymerization," we can reproduce the DNA that was in that unique cell and have enough of that DNA to make an analysis of it. With this technique, we can reproduce from one molecule of DNA millions of copies of the same molecule in just 24 hours. It's quite miraculous because it works faster than life but is just using tricks that life itself uses, that is, using a special enzyme and a special cycle that are normally used in life.
In 1990 it was published in England by Monk and Holding that, working on human embryos produced in vitro, they were able to remove one cell of those embryos, have the DNA of that cell polymerized, look at the DNA with a special probe, and determine whether those tiny embryos were male or female.
So even in an embryo a week old, with those new techniques, we can say already, "It's a man," or "it's a woman." It passes our imagination that lawyers knowing suddenly that this embryo a week old is a guy, or a girl, would not recognize at the same time that it is a human person.