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Gender

An Introduction to Gender, Sex, and Sexual Preference

Part 2: The heritable nature of gender.

Key points

  • There is much confusion in social media among the terms sex, gender, and sexual preference.
  • Gender refers to one's presentation or identification with stereotypic behaviors of a man, woman, or other.
  • Gender identification has a highly heritable basis that may be relatively independent of sex's heritability.
  • The prevalence of transgender people has increased recently due to greater acceptance and some social factors.

This post was co-authored by Frederick L. Coolidge1 and Apeksha Srivastava2

1Professor, University of Colorado, Colorado Springs, USA

2Doctoral Candidate, Indian Institute of Technology Gandhinagar, India

This post is Part 2 of a three-part series. Read Part 1 and Part 3.

AlexanderGrey/ Pixabay
Source: AlexanderGrey/ Pixabay

Overview: Many recent editorialists, particularly in regard to trans women (MTW) and trans men (WTM), have noted that a trans woman still possesses XY chromosomes, and a trans man still possesses XX chromosomes. These same editorialists subsequently castigate trans people for presenting or identifying themselves as women or men.

One major problem with their arguments is that they are conflating or misconstruing the scientific terms of sex, gender, and sexual preference and their individual heritable bases. The purpose of this series of posts is to delineate the three terms and provide a clearer basis for their use.

Sex, Gender, and Sexual Preference: What's the Difference?

Definition: The term gender refers to one's presentation or identification with the cultural stereotypic behaviors of a man, woman, both, or neither. The term sex refers to one’s biological genitalia (e.g., penis or vagina) at birth and the reproductive organs associated with them (e.g., testicles, ovaries, etc.). The term sexual preference (synonymous with sexual orientation) refers to the expressions of one’s predilections or sexual desires.

Gender (Part 2): The term gender refers to one's presentation or identification with the cultural stereotypic behaviors of a man, woman, both, or neither. These characteristics are often reinforced by the traditions of one’s culture, such as acting like a boy or girl, man or woman.

Gender: It's More Than Just Your Biological Sex

Gender characteristics may include external or internal behavioral or psychological traits like dominance, empathy, fathering, mothering, etc. In the past decade, the term cisgender has come to denote a person whose gender identity corresponds with their sex at birth. The prefix cis- comes from Latin, literally meaning "on this side of."

Transgender and Non-Binary People: Understanding Gender Identity

In contrast, the term transgender denotes a person whose gender identity differs from their sex at birth. A transgender or trans man (FTM) is a person whose assigned sex at birth was female, but their present gender identity is that of a male. A transgender or trans woman (MTF) is a person whose assigned sex at birth was male but whose present gender identity is that of a female.

It is also important to note that throughout history, and in nearly all cultures, some people have adopted gender-atypical states, such as men (XY) behaving like the cultural stereotypes of women, and women (XX) behaving like the cultural stereotypes of men. It is important to emphasize here that gender-atypical states (or gender nonconformity) are not synonymous with gender dysphoria, as not all gender-atypical states result in distress or dysphoria.

In some cultures, people in a gender-atypical state have been given a place of honor within their community or seen as possessing a unique spirituality. More recently, these gender-atypical states have been more often viewed as pathological or abnormal and were once labeled gender identity disorder, which implied that one’s gender preference was at odds with one’s biological sex.

Worldwide, the current term is gender dysphoria, which removes the negative connotation of the word disorder and highlights the distress that arises when one’s gender preference differs from one’s biological sex.

The scientific fact that gender preference is genetically heritable has either been ignored, disregarded, or politically misconstrued. Certainly, gender preference, to some extent, can be influenced by one’s culture and even popular social media, as attested by the increasing numbers of people over the past decade who identify as transgender.

However, the latter influence does not negate the scientific evidence for the heritability of gender preference. There is a firm consensus that intelligence is a highly heritable trait, and approximately 40 percent to 50 percent of its variability is attributed to genetic influences.

Note that this does not mean that there is a single gene or single gene location for intelligence, as multiple genes (a condition known as polygenic) contribute to one’s intelligence. It is interesting to note that gender preference has been shown to be more genetically heritable than intelligence and polygenic, as one twin study found gender preference up to 62 percent heritable.

The true prevalence of people who identify as transgender is controversial, but it is most commonly estimated at a worldwide 1 percent or less, and the prevalence of trans women is almost three times greater than of trans men. One issue in prevalence estimates, especially worldwide, is that some countries actively suppress (or worse) a transgender self-identification.

A few decades ago, identifying oneself as transgender might not have been illegal, but it would have certainly caused most of those people serious trouble with their families, friends, and society at large. Thus, the increase in the prevalence of people who identify as transgender undoubtedly reflects their greater acceptance and acknowledgment in contemporary society. That a psychiatric term (gender dysphoria) persists for transgender people is partial testimony to the continued difficulties they still encounter.

The term non-binary refers to people whose gender preference is neither male nor female. They may identify as having no gender identity, a separate gender identity, more than one gender identity, or a fluctuating gender identity. The term non-binary does not imply anything about biological sex or the sex assigned at birth, nor it is the same as being intersex.

Non-binary people may have various sexual preferences.

References

Coolidge, F. L., & Srivastava, A. (2023). Heritability of gender dysphoria in childhood, adolescence, and adulthood. In T. K. Shackelford (ed.), Encyclopedia of Sexual Psychology and Behavior (pp. 1–4). Springer.

Coolidge, F. L., Thede, L. L. & Young, S. E. (2002). The heritability of gender identity disorder in a child and adolescent twin sample. Behavior Genetics, 32, 251–257.

Englert, P., Dinkins, E. G., Fradella, H. F., & Sumner, J. M. (2016). An overview of sex, gender, and sexuality. Sex, Sexuality, Law, and (In)justice, 1–30.

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