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XY Girls – What is their gender identity? September 5, 2009

Posted by Geekgirl in anatomy, brain, Developmental, Gender Identity, genetics, Intersex.
Tags: , , , ,

Lately I’ve been publishing research on individuals who are XY but appear female or vice versa. This is called sex reversal. Depending on the cause, individuals may appear to be the opposite gender or somewhere in between. There are lots of terms used for people with ambiguous genitalia including hermaphrodites and intersex. The terms seem to change with the times and the understanding of the biological mechanisms.

This abstract is a little bit older. However, it contains something that most of these papers do not. What is the gender identity of these individuals? If a person has XY chromosomes, but female genitals, will they identify as female or male?

This abstract talks about two enzymes, which are proteins that are involved in the conversion of testosterone to dihydrotestosterone. Mutations in the genes that code for these enzymes can lead to a deficiency and the result can be an individual with XY chromosomes but female genitals. The genes are NOT on the XY chromosomes. Many people believe that it is only the X and Y chromosomes that give us our gender. This isn’t true. Genes from other chromosomes are needed. For more information, you can check Wikipedia, 5-alpha reductase and Wikipedia, 17-beta-hydroxsteroid.

These mutations are recessive and are inherited. For more information, visit http://ghr.nlm.nih.gov/condition=5alphareductasedeficiency

Archives of Sexual Behavior
Volume 34, Number 4 / August, 2005
Pages 399-410

Gender Change in 46,XY Persons with 5α-Reductase-2 Deficiency and 17β-Hydroxysteroid Dehydrogenase-3 Deficiency

Peggy T. Cohen-Kettenis

Department of Medical Psychology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, Netherlands

Abstract Individuals with 5α-reductase-2 deficiency (5α-RD-2) and 17β-hydroxysteroid dehydrogenase-3 deficiency (17β-HSD-3) are often raised as girls.

Over the past number of years, this policy has been challenged because many individuals with these conditions develop a male gender identity and make a gender role change after puberty.

The findings also raised doubts regarding the hypothesis that children are psychosexually neutral at birth and emphasized the potential role of prenatal brain exposure to androgens in gender development. If prenatal exposure to androgens is a major contributor to gender identity development, one would expect that all, or nearly all, affected individuals, even when raised as girls, would develop a male gender identity and make a gender role switch later in life.

However, an estimation of the prevalence of gender role changes, based on the current literature, shows that gender role changes occur frequently, but not invariably. Gender role changes were reported in 56–63% of cases with 5α-RD-2 and 39–64% of cases with 17β-HSD-3 who were raised as girls. The changes were usually made in adolescence and early adulthood. In these two syndromes, the degree of external genital masculinization at birth does not seem to be related to gender role changes in a systematic way.



1. Rob - September 6, 2009

This is a complicated topic. Realize that there are gradations in most of the forms of intersex-and different body systems respond differently to these syndromes.

For example, in the two enzyme-induced syndromes discussed above, these people suffer from deficiency. That means the enzyme isn’t 100% gone. The person may respond to some of the androgens produced by the body. A number of things can be going on. A promoter region can be defective, causing less of the enzyme to be made. The enzyme have a single-nucleotide polymorphism (SNP) that causes it to be 10% less effective, 90% less effective, degraded more rapidly by defective protein scavenging mechanisms, etc.

Given the wide variety of mechanisms eukaryotes use to regulate protein production, I doubt they were able to separate these individuals into various subtypes or even do more than some crude grading on how female the genitals were.

What if there’s a form of androgen insensitivity that only affects a small region of the brain that determines which sex one is attracted to? Or which sex one perceives one’s body to “actually” be?

This is only the beginning of a very complex subject.

2. Sex Hormones and the Brain – Part 2 « LGBT Latest Science - December 22, 2009

[…] condition occurs when a male fetus has a deficiency in certain enzymes, either 5alpha reductase-2 or 17beta-hydroxysteroid dehydrogenase-3. These enzyme deficiencies […]

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