Human Life Still Begins at Fertilization

  • By
  • January 10, 2020

Geneticist Ricki Lewis wrote an article in late 2013 called When Does a Human Life Begin? 17 Timepoints. The article was brought to my attention today which leads me to believe that it was recently re-posted, especially given the first paragraph. I decided to respond to the article because it highlights just how deceptive many so-called science experts are when it comes to the question of when human life begins.

Let’s start by analyzing a couple of Lewis’ claims in the very first paragraph. She starts off by claiming “Strong feelings always seem to trump biological facts”. I agree with her statement, except it’s usually pro-choice biologists who take feelings over biological facts. The biological fact that human life begins at fertilization was discovered in the mid-1800s and no discovery has ever been made to controvert this scientific fact. Indeed, scientific discoveries since that time have only served to bolster the claim that human life begins at fertilization. One such recent discovery was expounded in a paper published in 2016 that shows the remodeling events of the embryo necessary for implantation are all done by the embryo, independent of maternal tissues. [1] The embryo is a completely autonomous organism from fertilization. Furthermore, at the end of her article, she tells us that it is technology that defines, for her, when human life begins. This is not a scientific position, it is one that clearly avoids the scientific evidence.

At the end of her first paragraph, she arbitrarily tells us that an embryo is not a fetus and that this difference matters. Of course it matters. But who is making the claim that a four-week embryo is actually a fetus? I am not aware of anyone, nor does she link us to anyone who has made such a claim. The pro-life argument is not that we are conceived as fetuses, the pro-life argument is that it is wrong to intentionally kill an innocent human being, and since embryos and fetuses are innocent human beings, this makes it wrong to intentionally kill them, too. Lewis is completely clueless as to what pro-life people actually argue and so her article just amounts to another article that doesn’t contribute anything meaningful to the conversation. What’s worse, she is actually dishonest not just about the science, but she obfuscates the issue by conflating the philosophical and scientific senses of life, and claiming that science has no consensus on the matter. Of course, science does have a consensus on the matter. Steve Jacobs, a Ph.D. from the University of Chicago, recently published research showing that 96% of biologists agree that human life begins at fertilization. [2] You can find more experts who disagree about Darwinism than you can find who disagree about human life beginning at fertilization. How can Lewis be so ignorant about her own field?

Lewis says she has been in this business for decades. I’ve been studying abortion and human development (and now bioethics, generally) for roughly ten years. I’m not sure but considering her extreme level of ignorance of the scientific consensus, maybe she ought to take a step back and wonder if she should be embarrassed that she’s been in the business for so long and yet has such an elementary understanding of the field of biology when it comes to human life. She goes on to say that life is a question for a number of different fields, but this isn’t true. Politics, psychology, technology, and emotions have absolutely nothing to do about when human life begins. In fact, emotions often lead us astray. Humans are rational creatures, meaning that our rationality should win out over our emotions. If a geneticist or a doctor doesn’t understand this, God help us. Maybe that’s why there are so many atrocities that scientists are responsible for.

Philosophy can add to the discussion about what makes something alive, and it certainly has much to say about the value of things and about what rights a thing has. But if I see a human entity walking down the road and I want to know if that individual is alive, how do I determine this? Not through philosophical musing. I determine it through empirical observation. Things like the person is moving under his own power, he’s breathing, he notices my approach, etc. All of these things tell me that he’s alive because these are the things I would expect to see of an adult human being if that adult human being is alive. These are empirical observations, which science engages in. These are not philosophical arguments, nor are they religious arguments.

She asserts that life science books don’t make claims about when life begins. Well, I don’t know about life science books, but scores of embryology textbooks make that claim. In 1933, Alan Guttmacher wrote the following: “We of today know that man is born of sexual union; that he starts life as an embryo within the body of the female; and that the embryo is formed from the fusion of two single cells, the ovum and the sperm. This all seems so simple and evident that it is difficult to picture a time when it wasn’t part of the common knowledge.” [3] In 1970, Doctor Malcolm Watts wrote, “The result has been a curious avoidance of the scientific fact, which everyone really knows, that human life begins at conception and is continuous whether intra- or extra-uterine until death. The very considerable semantic gymnastics which are required to rationalize abortion as anything but taking a human life would be ludicrous if they were not often put forth under socially impeccable auspices.” [4] Doctor Watts is no “anti-choice” advocate. And more recently, embryologists Keith L. Moore and T.V.N. Persaud wrote, “Human development begins at fertilization when a sperm fuses with an oocyte to form a single cell, the zygote. This highly specialized, totipotent cell marks the beginning of each of us as a unique individual. The zygote, just visible to the unaided eye, contains chromosomes and genes that are derived from the mother and father. The zygote divides many times and becomes progressively transformed into a multicellular human being through cell division, migration, growth, and differentiation.” [5]

Lewis goes on to give a list of 17 points in which a biologist might claim that life begins, including puberty. This, of course, is ridiculous and relies on a faulty understanding of NASA’s definition of life, which is to illustrate how they could determine that an alien species, if any actually exist, might be considered to be “life”. That is not their definition of when an individual life begins. At any rate, Lewis offers no argument for any of these points, just asserting that because she can put them forth as alternatives, that must mean fertilization is only one of many different options. This is, of course, a terrible way to argue. Just because you can present a possible alternative doesn’t mean you’ve presented a case. Anything is possible. What matters is what’s plausible, and no point other than fertilization is plausible for when life begins. I’ve adequately shown that in this article. If Lewis disagrees, she’ll need to make a case for it.

Lewis ends her article by asserting that #14 on her list, the 21st week, is the point she assumes because then a “sustainable human life begins”. Here she’s made a subtle, but illegal, move. Her article up to this point has been about when “human life” begins, and now she claims week 21 because that’s when a sustainable human life begins. I don’t like to just assume critics of my position are dishonest (after all, one can simply be mistaken). But as she keeps claiming about how long she’s been in the business, it’s difficult to conclude that she doesn’t understand basic words and how they change the sentences they appear in. Either she’s dishonest or just doesn’t think about what she writes, as long as she can try and justify her own position, despite the bad arguments to get there. At any rate, yes, week 21 is around the point where the fetus can probably survive if he is born prematurely. But why does that matter? We’re talking about when human life begins, not when sustainable human life begins. I’ve more than shown how Lewis is mistaken about the scientific literature on this important question.

In her penultimate paragraph, Lewis states: “Having a functional genome, tissue layers, a notochord, a beating heart … none of these matter if the organism cannot survive where humans survive. This is just nonsense. Of course they matter. Any pregnant woman who is not abortion-minded believes her child matters from the moment she can detect his presence within her. Humans develop — that’s just what they do. They begin life inside the mother’s body, implant in her uterus after about a week, and develop to the point where the embryo/fetus can survive outside her body. Humans cannot survive on their own even for the first several years after birth, so this point of development inside the mother’s womb is essential not just for fetal development but also for the bonding experience between mother and child so the mother can grow attached to her own child and the child can instinctively know that his mother will be there to care for him because he can’t care for himself. Lewis tells us she’s a mother, but it’s inconceivable how she can’t understand the intimacy and the bond between mother and child in the first nine months of this child’s life.

Lewis finishes off her article by saying: “Until an artificial uterus becomes a reality, technology defines, for me, when a human life begins.” Of course it will matter until artificial uteri become a reality. At that point, in order to keep her view that abortion is permissible, she’ll have to come up with a different excuse to justify her pro-abortion stance. Her criterion of technology is a bad criterion, but she can’t even be counted on to be consistent with her own bad criterion. Lewis is not a geneticist I would want responsible for my health.


[1] Shahbazi, Marta N., et al, “Self-organization of the human embryo in the absence of maternal tissues”, Nature Cell Biology 18, pp. 700-708 (2016).

[2] Jacobs, Steven, “Biologists’ Consensus on ‘When Life Begins'” (July 25, 2018). Available at SSRN: or

[3] Guttmacher, Alan, Life in the Making: The Story of Human Procreation, New York: Viking Press, 1933, p. 3, emphasis mine.

[4] Watts, Malcolm, “A New Ethic for Medicine and Society,” California Medicine, September 1970.

[5] Moore, Keith L., T.V.N. Persaud, The Developing Human: Clinically Oriented Embryology, 11th Ed., 2019, p. 11