Finding Form: Defining Human Sexual Difference

Introduction

What is the nature of human sexual difference? What is it that defines the human male and female as such? This seems a simple enough question: it is resolved with a glance thousands of times each day by doctors, nurses, and new parents. Yet, the answer is not always so clear. Review of intersex disorders reveals that, at times, even nature herself appears confused as to how to resolve the question of sexual difference. Examination of contemporary literature on sexual difference further manifests layers of complexity that seem to belie the apparent simplicity found in delivery rooms. So, how is one to define the human male and female? Is the essential difference found in genes and genitals? Or is sex itself perhaps a set of societal functions, a “place” in a social discourse, a cultural construct that changes with hem lines and prevailing ideologies? Another way to state the above questions is in terms of form, for questions of identity are questions of form. What is the form through which an individual human becomes male or female? And what is the ontological status of such forms? Are they forms through which a human being has his or her being simply, or are they forms that modify a substance whose existence precedes them? Are they simple forms consisting of a single modification of a substance or, rather, kinds of compositions containing several elements unified in a single quality?

In this article, I will attempt to provide some answers regarding the formal cause of human sexual difference. I will argue that an individual’s sex comes to be through an accidental form, a quality of the human being that, though an accident, flows from the human essence and, so, merits the name “essential accident.” I will further argue that the forms of male and female do not consist in only one determination of the human substance, but rather are compositions of distinct elements of varying importance, the harmony of which constitutes the completion of these essential identities of the human person.

To reach these conclusions, the general method I will employ is to build my inquiry upon the foundation of the thought of St. Thomas Aquinas, attempting to bring his physics, metaphysics, and anthropology to bear upon the findings of contemporary science regarding the nature of human sexual difference. My goal is not historical, but rather an application of Thomas’s thought to what has been discovered about sexual difference in the centuries since he completed his work.

Sex, Gender, and Gender Dysphoria

When considering the nature of sexual difference, one frequently encounters proposed distinctions between sex and gender: sex is a matter of biology while gender is matter of psychology and social role and function.¹ As with all topics in the realm of sexual identity, there is disagreement as to precisely of what distinctions between sex and gender consist, which is prior to which, and whether these distinctions are valid at all.² Though this article will, perhaps, provide an understanding of human sexual difference that is relevant to possible distinctions between sex and gender, its scope does not directly include the clarification of such distinctions. Neither is its principal purpose to address the question of sexual identity from the perspective of gender dysphoria. Clearly, these are topics of great importance and contemporary urgency. However, while I think the arguments contained in this essay will be relevant to questions regarding the distinction between sex and gender and could provide some basis for further work on understanding gender dysphoria, such matters are not my primary focus.

With the above limitations in mind, the essay will unfold as follows. I will begin with a brief discussion of the common notions of sexual difference that come to the human mind in virtue of its rapport with reality. This general discussion will provide us with some provisional theses about sexual difference that will serve as starting points for further discussion. With some common ground underfoot, I will next consider whether the forms through which a human being is male or female are substantial forms or accidental forms. Having...