by Gerry Silverstein
In his essay “The Wonderful Mistake,” biology writer Lewis Thomas talks about the appearance of DNA in primitive single cell organisms 3 billion years ago. Over very long time intervals more complex multicellular organisms evolved and we now know the transition can be traced to changes in DNA, the genetic blueprint of life.
For complex multicellular organisms to grow and evolve their DNA must be duplicated every time a cell divides. In highly complex organisms like humans the process of genome duplication must approach perfection. Too many mistakes would irreversibly corrupt the genetic blueprint.
The enzyme responsible for replicating DNA in a human cell nucleus is known as DNA-polymerase. The time allotted to copy the diploid human genome is 5-8 hours and requires thousands of polymerase molecules working at a rapid pace in a complex and coordinated molecular ballet.
With so many polymerase molecules moving so fast during the duplication process how does the polymerase not make occasional mistakes? The answer is it most certainly does make mistakes but it has a proofreading ability that allows it to correct mistakes!
Well I should say the polymerase, and some other molecules, correct most of the mistakes.
When a complete genome duplication process has occurred on average 3 mistakes will appear in each set of maternal and paternal chromosomes of the newly created cell.
Those 3 mistakes are the drivers of evolution.
Lewis Thomas in his essay conveys that if humans had invented the process of genome duplication they would have made it perfect, and evolution would never have occurred!
How does this review of species evolution and DNA duplication relate to the abortion debate?
It has taken more than 60 million years of mammalian evolution, and 6 million years of hominid evolution, to “perfect” the enormously complex process of creating a human life.
Yet the abortion debate focuses almost exclusively on terminating the process of creation; never about the details that define the creation process itself.
Creating a human being begins with the union (termed fertilization) of a male sperm cell with a female egg cell, or ovum.
The union activates a development program that will ultimately convert the fertilized egg cell into a multi-trillion-cell organism.
Over a 7-day period, while initial cell divisions are ongoing, the tiny fertilized egg moves from the fallopian tubes to the uterus.
Upon arrival at the uterus the now multicellular entity (termed an embryo) directs the creation of a placenta in which all further developmental events occur.
Development is astoundingly fast.
By 21 days post fertilization (equivalent to week 5 of the pregnancy as the timeline of a pregnancy is based upon the date of the last missed period), the embryo is now 0.1 inches long and looks like a tadpole or a seahorse. On day 22 a primitive heart has formed and begins to beat (ultimately twice as fast as the mother’s heart).
At 28 days post fertilization the embryo has grown to 0.23 inches, the vertebral column (spine) has formed, as has arm buds that look like little wings.
Two days later, the embryo is now 0.26 inches and a developing face with nostrils, mouth, and hollows that will become the eyes can be visualized.
At 39 days post fertilization (about 7.5 weeks of pregnancy) the embryo is 0.4 inches long and has features of a tiny human being with the exception that the head is 25% of the entire body.
All organs have formed to some degree and the kidneys are releasing urine into the placenta’s amniotic fluid where it will be transferred to the maternal circulation for eventual discharge.
At 58 days post fertilization (week 10 of the pregnancy) the embryo, now referred to as a fetus, is 1.3 inches long and essentially a miniature human being, although a long way from being able to exist outside the mother’s body.
In the second and third trimester, organs that have formed in the first trimester will further develop and prepare the fetus to enter the world as a member of the human species.
Most abortions take place during the first trimester (approximately 12 weeks) of a pregnancy.
The most common method of abortion is referred to as “medication abortion”. It involves 2 drugs, one to stop development, and the other to induce contractions that will separate the embryo (or fetus) from the mother’s body.
Medication abortions can be safely done up to 10 weeks of pregnancy (56 days post-fertilization). At 10 weeks gestation the fetus is 1.3 inches long and development is advanced with all organs present and some functioning as in an adult.
Prevention of Unwanted Pregnancy
There are more than a dozen different approaches to contraception, 10 of which have efficacies of 99% or greater in perfect use. Moreover when 2 methods are used simultaneously, efficacy increases further.
In many states and with many insurance programs contraception methods are available with no or minimal co-pay.
In spite of effective methods of contraception and often minimal cost, it is estimated that more than 900,000 abortions occur every year in the US.
Why with multiple options for preventing unwanted pregnancies, and often available at minimal or no cost, do abortions still occur in very high numbers?
Data collected by CDC for the period 2017-19 detail that 30.3% of women between the ages of 18-49 at risk for unintended pregnancy (i.e., sexually active and not intending to get pregnant) were using no method of contraception. This translated into almost 20 million women.
Obviously men are equally responsible for avoiding unwanted pregnancies, and a significant number of women experience situations where it is not their intent to engage in sexual intercourse.
Nonetheless the reality is many millions of men and women are taking no precautions to prevent unintended pregnancies. In addition many couples do not follow “perfect” use directions of the contraception approaches or devices they employ.
Critical Review and Reflection
The process of creating a new human being, an organism whose complexity and abilities are more aligned with science fiction than science fact, is the result of tens of millions of years of mammalian evolution.
Many who engage in sexual intercourse do not desire a pregnancy to occur yet take no steps, or fail to employ contraception methods correctly, to prevent unintended pregnancies.
The end result for many involves a decision to terminate the pregnancy at a stage in development when some or all organs of the developing embryo have been created, although in rudimentary forms.
Those who advocate for the right of a (biological) woman to carry a pregnancy to term or abort the pregnancy in the first trimester, or at any stage, declare the right to be absolute.
But if the means are available to prevent unintended pregnancies, yet many millions of individuals do not avail themselves of these prevention options, what does this say about personal responsibility and the lack of appropriate consideration for an entity in the process of becoming a new human being?
Bill Clinton said that abortion should be safe, legal, and rare. I agree with Mr. Clinton, “conditionally”.
What is my condition?
Excluding the clear need for abortions where (1) a woman is at risk for serious harm if the pregnancy continues and (2) serious congenital malformations develop in the embryo-fetus, as well as women who become pregnant as a result of rape or incest and desire an abortion, I would define “rare” as a 90% reduction in the current number of abortions.
And what if that cannot be achieved?
That is a question I believe society urgently needs to address.
If not now then when?
The author lives in South Burlington and taught Human Health and Disease subjects at UVM for 22 years.