Wednesday, November 23, 2011

When Does Life Begin?

Photo:  Wellcom, UK
Implanted embryo. The start of a human, but not a human.
"Every biologist would agree that life begins at conception."
I heard that once during a debate, said by a passionate anti-choice person. Although passionate, he is also wrong.  I'm a biologist and I do not agree that life begins at conception, nor do any of my current colleagues, nor did any of my professors in univeristy, nor do the vast majority of doctors where I'm from.  This isn't because we hate life or babies, it's because the evidence to back up such a claim simply isn't there.

There is never a "dead phase" in the process of life, because life is continuous.  The precursors of a zygote were alive before they became a zygote.  Egg cells are alive and sperm cells are alive, containing genetic material packaged in protein complexes.   In fact, all cells are alive.  Every cell in every person's body is alive.   A fertilized egg has no more independent human attributes than, say, a liver cell, which, like a fertilized egg, possesses human DNA and is living, but is not a human being.

Human development is not precise.  It's a continual process, and embryos and fetuses develop at different rates.  Anti-choicers want an exact date, minute, and second to be pinned down for "when life begins," but we can't give it to them because, scientifically, it doesn't even make sense.

That is the problem in dealing with most anti-choicers.  They're either all or nothing; no in-betweens, no grey areas, no subtleties.   They tend to take the same approach with sexual orientation:  They want one, clear-cut "gay gene," preferably flashing in bright pink color on a chromosome. If they aren't given that, they automatically interpret it as meaning only heterosexuality is natural; anything else is a choice or caused by upbringing.  They fail to understand – or completely disregard – the fact that many innate traits are not wholly genetic, or genetic at all.  Many are polygenic, multifactorial, or, as in the case with sexual orientation and gender identity, largely hormonal.

Science isn't black and white.  Sexuality certainly isn't black and white, and neither is determining the 'personhood' of a zygote.  Just as a seed is not a tree and an egg is not a chicken, a zygote is not a human.  It is human, but is not a human.  "But a zygote is alive and it's human," a conservative Catholic man once said to me, "so how is it not worthy of protection?  What am I missing?" 

My reply:   gestation.   An acorn is not an oak tree, even though it is oak-kind.  When it becomes a seedling (analogous to birth), then it becomes an oak – a baby oak.   Gestation is what takes us from being potential human beings, to being categorical human beings.

The concept of life "beginning" at fertilization is intellectually unsound from the get-go.   I do, however, feel that abortion is unfortunate.  Nobody is "pro-abortion" or "pro-death," as some anti-choicers wrongly label us.  Nobody advocates for all pregnant women to abort their embryos and fetuses.  That is pattently absurd.

Abortion is an intensely private and personal matter best left between a pregnant woman, her physician, and, if she so chooses, her family.  Politicians, who have no knowledge of the private cirumstances surrounding such a decision, should have no place in that decision.

While I believe women must have the right to make their own decisions about their own bodies, I am also personally uncomfortable with the notion that abortion should be available "on demand" for the entire nine months of pregnancy.  In fact, in most nations where abortion is legal – even in the most liberal of nations – abortion is either restricted, or not allowed, during the third trimester.  While I certainly do not consider a zygote or an embryo to be a "baby," a fetus in its seventh month of gestation is another matter.  In light of that, I fall within the so-called neurological/viability view of development.

To clarify, I have absolutely no problem with abortion on demand during the first trimester and part of the second.  At the end of the second trimester, however, the ethical circumstances become dicey.  During the third trimester, in my opinion, abortion would be appropriate only under special circumstances, e.g. danger to the woman's health, or detection of severe fetal abnormalities (such that the fetus would not survive very long on its own, or would have an existence full of pain and suffering if it were to be born).

Other than these limited exceptions, the government should stay out of a woman's womb.  Period.

At the end of the second trimester, a fetus reaches a stage of development known as "viability."  This is the time at which a fetus could potentially survive on its own, i.e. outside the womb, if it were to be delivered prematurely.  Viability varies greatly among pregnancies.  About 25% of fetuses delivered at 23 weeks of gestation survive, while 60% delivered at 25 weeks survive, and 90% survive at 27 weeks.  Nearly all pregnancies are viable at week 28, and no pregnancies are viable before the 21st week.

Secondly, at approximately 24 weeks of development, the six layer cortical column structure is complete within the fetus, as are functioning synapses between axons and dendrites.  Thalamocortical connections develop at about 25 weeks.  Though sporadic brain waves can be detected at 21 weeks, genuine continuous brain waves do not begin until about week 28. 

Being a human requires having a brain.  Take the brain away, the body that's left isn't a human being.  Keep brain activity alive, you have a human.  Before approximately 33 days of gestation, an embryo has no brain at all. After that, a brain begins to form in a lengthy process

On a similar note, and answering the concern that embryos or fetuses feel pain (particularly during an abortion), the consensus of the scientific community is that the capacity for functional pain perception in a fetus does not exist before 29 or 30 weeks. 

Significantly, a 2005 New Zealand study conducted by David Mellor detected the presence of certain chemicals in human and animal fetuses.  These include adenosine, which suppresses brain activity; pregnanolone, which relieves pain; and prostaglandin-D2, which induces sleep.  These chemicals are oxidized with a newborn's first few breaths and washed out of the tissues, allowing conciousness to occur at the moment of birth.   The fetus, however, is essentially lulled into a near-continuous slumber, rendering it effectively unconcious no matter the state of its anatomy.

For legal purposes, death is treated as the cessation of brain activity.  In other words, life ends when an EEG (electroencephalogram) pattern is no longer present.  Perhaps it is consistent and reasonable that life might mirror that on the other end of the spectrum.  The neurological view adheres to brainwave criteria.  Distinct human consciousness could be said to begin when a distinct EEG pattern can be detected.   Personally, I believe this to be true.  Coincidently, this fits nicely with the time at which viability tops the 50% mark: approximately 24 weeks.

Also coincidently, this follows the legal pattern of most modern democracies where abortion is legal, including my home country, Norway.  Current Norwegian law, for example, allows abortion on demand within the first trimester of gestation, by application from the beginning of the 13th to the end of the 18th week, and only under special circumstances thereafter.  Given the ramifications of fetal neurology and viability, I feel that the law is appropriate. 

Ninety-five percent of applications for abortions between the 13th and 18th weeks are approved by special commitees, though they comprise only 2.28% of annual abortions.  Abortions after the 22nd week of gestation are technically illegal in my country, as the Health Directorate has stated that any time after the start of the 23rd week, falls within the stage of viability.  Abortion may be allowed after the 22nd week, however, in cases where the mother's life or physical/psychiatric health is at risk, or where serious fetal anomalies are detected. 

Just over 97% of all abortions in Norway occur before the 12th week of gestation, and 75% of those within the first 9 weeks.  Roughly 80% of all abortions are medical (carried out by taking the abortion pill) rather than surgical, including all abortions occurring before 9 weeks gestation.

I understand that this is a tough topic and a source of endless opinion and debate.  However, I stand by my reasoning that abortion should be legal (and subsequently safe), at least during the first 18 weeks.

But legally when do we have a new human being?  When birth takes place.  After all, we don't celebrate our "conception day" or even our "viability day."   Birth, which can be pinpointed easily, must obviously be our sole factor in determining legal personhood.  Before that, there is "life," of course, but not a legal human being.  There's more to being human than possessing a cell with the right combination of genes.

Fertilization simply is not a rational point at which to declare instant personhood.  To call every zygote a human being from the moment of fertilization is, quite frankly, absurd, as roughly 50% of all zygotes do not even survive to implantation.  Of those that do implant, a further 25% spontaneously abort by the sixth week, and another 7% miscarry or are stillborn.

Are anti-choicers really hinging their bets on the theory that God, in His infinite wisdom, set up our biology in such a way that roughly 80% of all "human beings" created end up in landfills?  This paints a rather grim picture of God, essentially turning Him into the biggest abortion provider of all, for there are far more nascent entities terminated by natural causes ("God's will") than by induced abortion.  Shall we next await a papal condemnation of God?   If zygotes and embryos are human beings, should we not be holding funerals for the 80% that God allows to be discarded naturally?

One of the best known developmental biologists on the planet today is Dr. Lewis Wolpert of University College London, and he happens to be the author of an excellent textbook for undergraduate studies entitled Principles of Development. In it he sums up the matter quite well:

"What I'm concerned with is how you develop.  I know that you all think about it perpetually, that you come from one single cell of a fertilized egg.  I don't want to get involved in religion but that is not a human being.   I've spoken to these eggs many times and they make it quite clear ... they are not a human being."


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