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The Specification of Sex/Gender in the Human Species: A Thomistic Analysis

Published online by Cambridge University Press:  01 January 2024

Nicanor Pier Giorgio Austriaco O.P.
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Abstract

To develop a philosophical framework to address the specification of sex/gender in humans, I will begin by summarizing what we know about the biology of sex determination in human beings. Basically, sex/gender is specified by several networks of genes anchored in the genetic interaction between the two genes, Sry and Sox9. Next, I will propose that this biological mechanism is best understood within a philosophical anthropology that embraces insights taken from systems biology to articulate a hylomorphism that explains the integrity, dynamism, and teleology of the human organism. The systems perspective described here represents one attempt to reformulate the received philosophical framework of classical Aristotelian-Thomistic hylomorphism so that it incorporates the insights of modern biology. Finally, I will use the systems perspective and key principles articulated by St. Thomas Aquinas in his philosophy of nature to identify criteria that could be used to specify the sex/gender of a particular human being: The most certain criterion for maleness would be the capacity to produce sperm while the most certain criterion for femaleness would be the complementary capacity to produce eggs. Deviations from this criterion would decrease the certitude of our judgment regarding the sex/gender of the individual.

Keywords

sex/gender specificationsystems perspectivehylomorphismsex determinationgender identity disorder
Type
Original Article
Information
New Blackfriars , Volume 94 , Issue 1054 , November 2013 , pp. 701 - 715
Copyright
Copyright © 2013 The Author. New Blackfriars © 2013 The Dominican Council.

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References

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6 The summary of sex determination that follows is based upon the following reviews: Quinn, A. and Koopman, Peter, “The molecular genetics of sex determination and sex reversal in mammals,” Semin Reprod Med. 30 (2012): 351–363CrossRefGoogle ScholarPubMed; Sekido, Ryohei and Lovell-Badge, Robin, “Sex Determination and SRY: Down to a Wink and a Nudge?” Trends Genet 25 (2008): 19–29CrossRefGoogle Scholar; and Wilhelm, Dagmar, Palmer, Stephen, and Koopman, Peter, “Sex Determination and Gonadal Development in Mammals,” Physiol Rev 87 (2007): 1–28CrossRefGoogle ScholarPubMed. Relevant citations to the scientific literature can be found in these reviews.

7 For concise overviews of systems biology, see both Hartwell, L., Hopfield, J.J., Leibler, S., and Murray, A.W., “From Molecular to Modular Cell Biology,” Nature 402 (1999): C47–52CrossRefGoogle ScholarPubMed; and Kitam, H., “Systems Biology: A Brief Overview,” Science 295 (2002): 1662–1664CrossRefGoogle Scholar. For examples of how the systems perspective is changing the way biologists understand biological processes, see Kicheva, A., Cohen, M., and Briscoe, J., “Developmental Pattern Formation: Insights from Physics and Biology,” Science 338 (2012): 210–2012CrossRefGoogle ScholarPubMed; and Furusawa, C. and Kaneko, K., “A Dynamical-Systems View of Stem Cell Biology,” Science 338 (2012): 215–217CrossRefGoogle ScholarPubMed. A good introduction to systems theory written for the non-scientist can be found in Kauffman, Stuart, At Home in the Universe (New York: Oxford University Press, 1995)Google Scholar; and in Barabesi, Albert-Laszlo, Linked: How Everything is Connected to Everything Else and What It Means (New York: Plume, 2003)Google Scholar. This discussion of systems biology is based, in the most part, on my essays, ‘On Static Eggs and Dynamic Embryos: A Systems Perspective’, National Catholic Bioethics Quarterly 2 (2002), pp. 659–83CrossRefGoogle Scholar; and ‘Immediate Hominization from the Systems Perspective’, National Catholic Bioethics Quarterly 24 (2004), pp. 719–38Google Scholar.

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9 For calculations in support of this claim, see my essay, “The Pre-implantation Embryo Revisited: Two-celled Individual or Two Individual Cells?” Linacre Quarterly 70 (2003): 121–126CrossRefGoogle Scholar.

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11 This approach is particularly attractive to the Catholic tradition, which committed itself to Aristotelian-Thomistic language in 1312 when the Council of Vienne defined de fide that the human soul is the form of the body (Denzinger-Schonmetzer no. 902; cf. Catechism of the Catholic Church, no. 365.)

12 For a good summary of classical hylomorphic theory, see Wallace, William A. OP, The Elements of Philosophy (New York: Alba House, 1977), pp. 41–84Google Scholar; and Brower, Jeffrey E., “Matter, Form, and Individuation,” in The Oxford Handbook of Aquinas, ed. Davies, Brian and Stump, Eleonore (Oxford: Oxford University Press, 2012), pp. 85–103Google Scholar.

13 The human form or soul is an exception to this rule since it can exist apart from the material principle. However, as so existing, the soul is not a complete person. For discussion, see Anton Pegis, St. Thomas and the Problem of the Soul in the Thirteenth Century (Toronto: Pontifical Institute of Mediaeval Studies, 1934).

14 As noted earlier, the systems perspective presented here presupposes the metaphysical framework put forward by classical hylomorphic theory. Given the dynamic nature of the human body which is continually undergoing molecular change, anyone who rejects the distinction between living substances and non-living aggregates would have to conclude that he or she can only exist and be identified as a distinct and unique human individual for a maximum of two years. This, I believe, is obviously ludicrous. For a modern defense of the substantiality of the human person, see J.P. Moreland and John Mitchell, “Is the Human Person a Substance or a Property-thing?” Ethics & Medicine 11 (1995): 50–55.

15 Body composition data was obtained from Report of the Task Group on Reference Man, International Commission on Radiological Protection (New York: Oxford University Press, 1975).

16 Again, systems hylomorphism presupposes the classical conviction that the human soul is immaterial and subsistent. For a clear summary of the arguments for this view, see Shanley, Brian J. O.P., The Thomist Tradition (Dordrecht: Kluwer Academic Publishers, 2002), pp. 153–166CrossRefGoogle Scholar. Also see the paper by Klima, Gyula, “Aquinas on the Materiality of the Human Soul and the Immateriality of the Human Intellect,” Philosophical Investigations 32 (2009): 163–182CrossRefGoogle Scholar.

17 For a popular discussion of emergence and the emergent properties of different systems, see Johnson, Steven, Emergence: The Connected Lives of Ants, Brains, Cities, and Software (New York: Scribner, 2001)Google Scholar. For philosophical analysis, see O'Conner, Timothy, “Emergent Properties,” Amer. Phil. Quart. 31 (1994): 91–105Google Scholar.

18 For two studies on the robustness of biological systems, see Wagner, A., “Robustness against mutations in genetic networks of yeast,” Nature Genetics 24 (2000): 355–361CrossRefGoogle ScholarPubMed; Gu, Z. et al., “Role of duplicate genes in genetic robustness against null mutations,” Nature 421 (2003): 63–66CrossRefGoogle ScholarPubMed; and El-Samad, H. et al., “Surviving heat shock: Control strategies for robustness and performance,” Proc. Natl. Acad. Sci. USA 102 (2005): 2736–2741CrossRefGoogle ScholarPubMed.

19 In the jargon of systems theory, the hub-spoke system is called a scale-free network. For a review, see Oltvai, Z. N. and Barabasi, A., “Systems Biology: Life's Complexity Pyramid,” Science 298 (2002): 763–4CrossRefGoogle ScholarPubMed. For studies involving scale-free networks in living systems, seeJeong, H. et al., “Centrality and Lethality of Protein Networks,” Nature 411 (2001): 41–42CrossRefGoogle ScholarPubMed; Ravasz, E. et al., “Hierarchical organization of modularity in metabolic networks,” Science 297 (2002): 1551–5CrossRefGoogle ScholarPubMed; and Han, J. J. et al., “Evidence for dynamically organized modularity in the yeast protein-protein interaction network,” Nature 430 (2004): 88–93CrossRefGoogle ScholarPubMed.

20 Wisniewski, A.B. et al., “Congenital Micropenis: Long-term Medical, Surgical, and Psychosexual Follow-up of Individuals Raised Male or Female,” Horm Res 56 (2001): 3–11Google ScholarPubMed.

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22 Rettew, D.C., “Apples to committee consensus: the challenge of gender identity classification,” J Homosex 59 (2012): 450–459CrossRefGoogle ScholarPubMed.

23 Dhejne, C. et al., “Long-term follow-up of transsexual persons undergoing sex reassignment surgery: cohort study in Sweden,” PLoS ONE 6 (2011): e16885CrossRefGoogle ScholarPubMed. The study concluded the following: “This study found substantially higher rates of overall mortality, death from cardiovascular disease and suicide, suicide attempts, and psychiatric hospitalisations in sex-reassigned transsexual individuals compared to a healthy control population. This highlights that post surgical transsexuals are a risk group that need long-term psychiatric and somatic follow-up. Even though surgery and hormonal therapy alleviates gender dysphoria, it is apparently not sufficient to remedy the high rates of morbidity and mortality found among transsexual persons.”

24 This paper was first read at the Aquinas Seminar hosted by the Aquinas Institute of Blackfriars Hall, Oxford, on March 4, 2010. I thank William Carroll and the Dominican friars at Blackfriars for their kind invitation to visit the United Kingdom, and to the participants at the seminar for stimulating discussion.