SEX
Executive summary
Sex most commonly denotes the biological classification of organisms into categories such as male and female based on reproductive anatomy and gamete production, but the term is also used in legal, medical, and everyday language to mean sexual activity or the social category that overlaps with gender [1] [2] [3]. Public debate sharpens around edge cases—intersex conditions, definitions in law, and whether “sex” should be treated as strictly binary or as a spectrum—positions that are reflected across medical, academic, and political sources [4] [5] [6].
1. What dictionaries and medical glossaries say about sex
Standard dictionaries and medical glossaries frame sex as the biological state of being male, female, or intersex, often referring to reproductive anatomy, sex chromosomes, and related physiological traits; Cambridge and Stanford glossaries both emphasize physical distinctions such as chromosomes, anatomy, and reproductive function [7] [8]. Merriam‑Webster’s primary entry likewise defines sex as the two major biological forms distinguished especially by reproductive organs, while vocabulary resources note the word’s parallel use to mean sexual activity between people [2] [3].
2. The biological core: gametes, determination systems, and variety across life
In biological and evolutionary contexts, sex is defined by gamete type—organisms producing small gametes are called male and those producing larger gametes are called female—and sex determination can rely on chromosomal systems (like XY or ZW) or environmental mechanisms such as temperature in some reptiles [1]. Wikipedia’s treatment underscores that sex is a trait of anisogamous species tied to gamete production and that many taxa show diverse sex‑determination systems and sexual dimorphism, highlighting that biology itself is not a single, uniform rule [1].
3. Sex, gender, and where definitions split
Health and research bodies draw a line between sex and gender: sex denotes biological attributes while gender refers to socially constructed roles and identities, a distinction used explicitly by CIHR and Medical News Today in their explanations of terminology and policy implications [5] [9]. The World Health Organization stresses that sexual health and related policy require attention to both biology and broader concepts of sexuality and rights, indicating operational reasons for keeping the distinctions clear in public health work [10].
4. Everyday meanings and contested borders—activity, intimacy, and experience
Popular and clinical discussions also use “sex” to mean sexual activity; consumer health sites and lexicons often treat vaginal intercourse and other intimate acts as commonly accepted definitions of sex, while sex therapists and behavioral researchers highlight the variety of lived definitions and how personal experience shapes what people call “having sex” [11] [12]. Surveys and psychological literature find dozens of operational definitions in practice, which affects everything from consent conversations to epidemiological data collection [12].
5. Intersex, spectrum arguments, and numbers in the debate
Education and social science sources report that intersex conditions—variations in chromosomes, gonads, hormones, or genitalia—occur with measurable frequency and are the basis for arguing that sex may be better described as a spectrum rather than an absolute binary, with some textbooks estimating intersex prevalence around 1–1.7% of births [4]. Medical glossaries acknowledge variation in sex markers and the complexity that creates for binary frameworks, a biological fact often invoked in academic and advocacy contexts [8] [4].
6. Legal and political framing: absolutism versus accommodation
Some policy organizations advance an absolutist, binary definition of sex for statutes and regulations—The Heritage Foundation’s model legislation explicitly asserts two and only two sexes and argues that sex should not be determined by identity—an expressly political position aimed at resolving perceived ambiguities in law but one that has prompted pushback from medical and human‑rights voices that note biological variation and rights implications [6]. These competing agendas underline how definitions of sex are not merely semantic but shape access, protections, and health policy [10] [6].