Gender vs. Sex in Biology and Society

Our vocabulary fails to capture reality

Alicia M Prater, PhD
Maeflowers
Published in
7 min readApr 3, 2022

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a red bird faces left and a grey bird faces right
Photo by Brock Kirk on Unsplash

Before the 1950s, and still for several decades after the fields were enlightened, medicine and science had assumed that society’s gender roles were driven by biology. This resulted in the fallacy of gender dichotomy and binarism. With the discovery of DNA and an understanding of how secondary sexual characteristics are determined, it became even clearer that dividing humans into two categories should be limited to reproduction.

In Science, we’re still trying to untangle the traditional conflation of sex and gender, with journals composing inclusivity statements and guidance on word choice even while researchers try to break the habit of focusing on men in health-related studies. In medical research, we need to be able to parse out hormonal and development effects by having gendered cohorts, but the intention isn’t to exclude a particular identity, so getting the language right is necessary.

Defining Gender and Sex

Genotypic gender

So-called genotypic gender is determined at conception. Genotype means the genetic code. Phenotype is the physical manifestation of that code (via gene expression). So genotypic gender is based on the sex chromosomes, which in humans is usually 46XX (female) and 46XY (male) because of the dichotomous nature of our sexual reproduction capacity. The number refers to the number of chromosomes in the genome, with X and Y as the sex chromosomes (Y is the traditional male sex chromosome). However, some variations in genotypic gender exist because of sex polysomies, which I discuss below.

The process of conception in humans is the fusion of one egg donated by the mother (who has a female reproductive system) and one sperm donated by the father (who has a male reproductive system). From each of these sex cells, each parent donates half of the chromosomes the child will have — 22 autosomal chromosomes and a sex chromosome, for a total of 23 chromosome pairs (46 total chromosomes) in the embryo. The sex chromosome from the mother is always X because the female genotype is XX. The sex chromosome from the father may be X or Y, with a 50:50 chance under normal circumstances. Thus, the genotypic gender of the embryo and…

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Alicia M Prater, PhD
Maeflowers

Scientific editor with Medical Science PhD, former researcher and lecturer, long-time writer and genealogist