In recent years, questions surrounding the LGBTQ+ community and their continued acceptance into society has been a hot topic. Never having been particularly impacted by this topic—despite having grown up in an area of California which has an open discussion about the issue—I hadn’t given it much thought. I didn’t have any negative feelings towards the LGBTQ+ community; I just didn’t understand them. I had always assumed that there was no logical explanation for those who struggled with gender identity other than mental illness. It wasn’t until my college science courses that I began to understand the complexities of what determines gender expression and how wrong I had been.
I quickly learned that the process which determines the sex of an organism is a vastly complex system that we still do not fully understand. When any part of this complex system is altered, it can potentially result in what are called “disorders of sexual development.” This term is controversial and has since shifted towards a more moderate phrase: variations of sexual development. Could these variations have an impact on a person’s perception of their gender?
To help us understand this concept, let’s introduce ourselves to some basics of how sex is determined. In humans, the biological default is female. It’s only if the sperm fuses its Y chromosome with the egg’s X chromosome that the organism will develop into a male. The sex-determining region of the Y chromosome (SRY) will suppress the development of female reproductive organs, while promoting the production of male reproductive organs.1
However, if a mutation occurs in this region of the Y chromosome, the organism may develop as a female despite having the male genotype (set of genes).2 Even if the Y chromosome is normal, other conditions such as androgen insensitivity syndrome (AIS)—a condition in which varying levels of a person’s cells do not respond to androgenic hormones such as testosterone—can result in a range of anything from an under-masculinized male to a phenotypic (regarding observable traits resulting from genes) female individual with a male genotype.3 AIS is an example of a condition caused by variations in the developmental process which may result in a range of sexual expression, including ambiguous genitalia. The state of being anything other than fully male or female is referred to as intersex.
Other conditions exist which may result in both male and female cells in the same body. This condition, called chimerism, is caused by more than one fertilized egg merging into the same embryo during development.4 Genetically-distinct cells which would normally develop into fraternal twins will begin to develop into the same body.
Although variations in sexual development are rare in humans (up to 1.7 percent of live births),5 it is important to remember that thousands of people live with these conditions which have a major impact on their lives and sense of identity. Being intersex can contribute to the occurrence of a discrepancy between the gender assigned at birth and the gender someone identifies with, a state known as gender dysphoria.6 Additionally, many people with intersex conditions have to deal with infertility.7
The realization that the more we learn about the world around us the less we really know certainly applies to human biology. As we learn more about how sex is developed, we continue to discover the complexities of this process and the potential alterations which may lead to a variation in the expression of sex as a person develops. I have covered only a few of the many conditions which may result in a variation of sexual development; however, dozens more exist. Although no one can say that variation in sexual development is the exclusive cause of gender dysphoria, it is widely believed to be a contributing cause.