While biologists’ consensus view that a human’s life begins at fertilization might be unexpected for some, it is expected given the underlying biological facts. Mammalian reproduction begins with the fusion of a male’s sperm and a female’s egg and results in a new mammalian organism. This new organism is a single cell called a ‘zygote’, and it is in the first stage of the mammalian life cycle. When a zygote is the result of a human sperm’s fertilization of a human egg, the zygote has a human genome that is distinct from both of its parents. Therefore, based on its biological classification, rooted in its genetics and development in the human life cycle, the zygote can be described as a Homo sapiens zygote (i.e., a human) to distinguish it from a Felis catus zygote (i.e., a cat). This is not controversial. However, there has been some debate on the uniqueness of a human zygote compared to other human cells.
Through gene expression, human cells differentiate to perform specialized functions in the body. A zygote is unique as it is a totipotent cell that often becomes “a fertile, adult individual” through generating all cells of a body and organizing them “in a specific temporal and spatial sequence”. It is further unique in that it is the only single cell that is developing in the human life cycle. Accordingly, the biological stance on when a human’s life begins would succinctly state: ‘a human zygote is an organism with the human genome that is in the first stage of the human life cycle.’ This is a descriptive view based on observable traits, that recent findings suggest is a biological statement largely uncontested by the biological community.
Just as important as ‘when life begins’ is Americans’ understanding of it. Americans were asked (1) when a human’s life begins, (2) when a biological human’s life begins, (3) when a fetus deserves legal protection, (4) when a fetus deserves legal protection outside of the abortion context, (5) when a fetus deserves constitutional rights, and (6) when surgical abortions should be illegal if an artificial womb were created; their responses to the questions were remarkably related.
This means that Americans have a very stable view of when a human’s life begins, whether one asks their biological view, their philosophical view, or their legal view. 82% of Americans believe it is an important question in the debate, 93% affirmed that a human’s life is worthy of legal protection once it begins, and 76% suggested that Americans deserve to know when a human’s life begins to be informed in their abortion positions and decisions.
While half of pro-choice Americans believe a fetus should only be recognized as a human under the U.S. Constitution at viability or birth (51%), very few pro-life Americans do (6%). When asked how to resolve the question of when life begins, 80% of Americans suggested that biologists were most qualified to determine when a human’s life begins; 91% suggested they made their selection because biologists are objective experts in the study of life. When they were asked to anticipate what biologists would say, 23% of pro-choice and 54% of pro-life Americans anticipated that biologists would affirm the view that a human’s life begins at fertilization. However, thousands of biologists were surveyed from over one thousand academic institutions around the world, and 96% affirmed at least one statement representing the view that a human’s life begins at fertilization.
Seisenberger, S. et al. “Reprogramming DNA methylation in the mammalian life cycle: building and breaking epigenetic barriers”. Phil. Trans. R. Soc., 2012.
Wildman D.E., Goodman M. “Humankind’s Place in a Phylogenetic Classification of Living Primates”. In: Wasser S.P. (eds) Evolutionary Theory and Processes: Modern Horizons. Springer, 2004, p. 293.
Anne, L. “Anti-Abortion Argument #1: It’s a Person”. Love, Joy, Feminism, 2012, available at: http://www.patheos.com /blogs/lovejoyfeminism/2012/09/arguments-against-abortion-its-a-person.html.
Condic, M.L. “Totipotency: What it is and what it is not”. Stem Cells and Development, 2014, 23(8), p. 796-812, available at: https://doi.org/10.1089/scd.2013.0364.
With recent technological advancements, biologists are now able to use observable genomic DNA to biologically classify a single-celled organism as a member of a species; modern biological classification methods make use of such genetic analyses in concert with classic methods that utilize morphological and phenotypical characteristics; see, for example: Kouduka, M., Sato, D., Komori, M. et al. “A Solution for Universal Classification of Species Based on Genomic DNA”. International Journal of Plant Genomics, Article ID 27894, 2007, 8 pages, available at: https://doi.org/10.1155/2007/27894.
Jacobs, S.A., Balancing Abortion Rights and Fetal Rights: A Mixed Methods Mediation of the U.S. Abortion Debate (2019), p. 295, available at: https://knowledge.uchicago.edu/record/1883.
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Id.at p. 250.