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Intersex. Cause, Treatment, and Ethics July 28, 2009

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

Intersex. It’s a physical condition that not many of us understand. Essentially, it is when it is difficult to tell the sex of a child by their genitalia. Is it a girl or is it a boy? When we hear these things, because it is so rare, our minds tend to put these individuals into the “freak” category. Something we should never do to any human.

It is also a controversial topic in the LGBT community. Should it be corrected at birth? How do you know which gender is the right one? Not to mention, the surgical results are often less than satisfying.

What causes a person to be born with ambiguous genitalia?

One cause, in girls, is a condition known as congenital adrenal hyperplasia. It occurs in about 1 in 15,000 newborns (that number includes boys). Let’s stop here and make two important points. Not everyone with CAH will be intersex, not everyone who is intersex will have CAH.

I came across a recent paper describing a treatment that is administered in the womb. I’m going to walk through the science first, then have a few comments. I suspect this topic may draw a lot of different opinions so please feel free to comment.

Let’s start with congenital adrenal hyperplasia, abbreviated CAH because it’s a mouthful. It is a group of inherited disorders caused by a deficiency of an enzyme that helps make steroids. In this paper, they studied one particular enzyme known as 21-OHD CAH. The classical form of 21-OHD CAH does often result in ambiguous genitalia.

How does this happen? Progesterone is converted to androstenedione, which is a masculine hormone, instead of progressing to aldosterone. It is important to note that CAH has a lot of symptoms, not just incorrectly formed genitals, that reduce quality of life. Besides ambiguous genitalia, individuals experience vomiting due to salt wasting that can lead to dehydration and death, rapid growth in childhood, precocious puberty or failure of puberty to occur, menstrual irregularity and lack of ovulation.

If you are interested in CAH, Wikipedia has a good article in relatively simple terms.  It also has a nice picture of the hormone pathways.


Back to CAH. The critical time for sexual differentiation of external genitalia is at 7 to 12 weeks of gestation. For girls with CAH, this can result in external genitals that may look more male like. Yet, internally, the girls have a normal uterus and ovaries. Below is an image showing the gradient from a “normal” girl to a “normal” boy.

So how is this treated in the womb? It’s rather simple.

First, determine if it is a boy or a girl using chorionic villus sampling or amniotic fluid and then checking if the child has two XX chromosomes (girl) or an X and a Y chromosome. If it’s a male, there is no treatment necessary.

If it’s a girl, then a more refined analysis of the DNA is performed to determine if the gene that codes for the enzyme is mutated or, in other words, defective. The mother is then given a drug called dexamethasone. This drug prevents the abnormal build up of the androstenedone and the genitals develop normally.

The paper ends by saying that there are few side effects in the children both physically and psychologically.

Now comes the commentary.  I do want to point out before I begin that the goal of this treatment is strictly to alter the course of physical genital development so that these children do not need unsatisfactory surgery later on. I also want to remind you that CAH has other symptoms that are NOT related to sexuality.

However, the authors also state that there is a decrease in girls with masculine behaviors. So psychology, behavior and possibly sexual orientation could be affected. What happens if these girls are not treated, besides the changes in genital development? Do these girls typically grow up to be lesbians, transgendered, bisexual? If they are assumed to be male (which will happen if the child is born in a place without the ability to look at their chromosomes, do they grow up to be straight men or gay men?

Women with CAH are usually heterosexual, however there is an increase in women who are bisexual or lesbian (please see the second abstract below).

Are we changing people into straight people? Should these children be left alone to develop as their genes are programmed to? I’m not the first person to ponder the ethical issues of changing sexual orientation in the womb.  If we were talking about strictly changing sexual orientation, I would not see any point in treating that. Gender identity? I don’t know. Individuals have surgery later in life. If we could determine their brain gender identity, then alter genital development, should we? It’s when we get into the realm of our physical anatomy that I think the question becomes more gray. And back to intersex girls. Without this treatment, they will experience a host of other symptoms that, to me, do not sound very pleasant.

Saroj Nimkarn, Maria I. New
Department of Pediatrics, Mount Sinai School of Medicine, USA
Molecular and Cellular Endocrinology
Volume 300 (year 2009) pgs. 192-196

Prenatal diagnosis and treatment of congenital adrenal hyperplasia due to 21-hydroxylase deficiency


Congenital adrenal hyperplasia (CAH) applies to a group of inherited disorders caused by an enzyme deficiency in steroid biosynthesis. The most common form of CAH is 21-hydroxylase deficiency (21-OHD), which in its severe form can cause genital ambiguity in females.

Affected females experience virilization both physically and psychologically. Steroid 21-OHD can be diagnosed in utero through molecular genetic analysis of fetal DNA. Appropriate prenatal treatment by dexamethasone administration to the at-risk pregnant mother is effective in reducing genital virilization in the fetus, thus avoiding unnecessary genitoplasty in affected females.

Current data from large human studies show that prenatal diagnosis and treatment are safe in the short term for both the fetus and the mother. Preliminary data from long-term studies support these results.

© 2008 Elsevier Ireland Ltd. All rights reserved.

And a second abstract, discussing the relationship between androgen excess and sexual orientation in girls with CAH, both classical and non-classical.

Arch Sex Behav. 2008 Feb;37(1):85-99.

Sexual orientation in women with classical or non-classical congenital adrenal hyperplasia as a function of degree of prenatal androgen excess.

Meyer-Bahlburg HF, Dolezal C, Baker SW, New MI.

New York State Psychiatric Institute & Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA.

46,XX individuals with classical congenital adrenal hyperplasia (CAH) due to deficiency of  the enzyme, 21-hydroxylase, show variable degrees of masculinization of body and behavior due to excess adrenal androgen production.

Increased bisexuality and homosexuality have also been  reported. This article provides a review of existing reports of the latter and presents a new study aimed at replicating the previous findings with detailed assessments of sexual orientation on relatively large samples, and at extending the investigation to the mildest form, non-classical (NC) CAH.

Also, this is the first study to relate sexual orientation to the specific molecular genotypes of CAH. In the present study, 40 salt-wasters (SW), 21 SV (simple-virilizing), 82 NC, and 24 non-CAH control women (sisters and female cousins of CAH women) were blindly administered the Sexual Behavior Assessment Schedule (SEBAS-A, 1983 ed.; H. F. L. Meyer-Bahlburg & A. A. Ehrhardt, Privately printed).

Most women were heterosexual, but the rates of bisexual and homosexual orientation were increased above controls not only in women with classical CAH, but also in NC women, and correlated with the degree of prenatal androgenization. Classifying women by molecular genotypes did not further increase the correlation.

Diverse aspects of sexual orientation were highly intercorrelated, and principal components analysis yielded one general factor. Bisexual/homosexual orientation was (modestly) correlated with global measures of masculinization of non-sexual behavior and predicted independently by the degree of both prenatal androgenization and masculinization of childhood behavior.

We conclude that the findings support a sexual-differentiation perspective involving prenatal androgens on the development of sexual orientation.

PMID: 18157628 [PubMed – indexed for MEDLINE]



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

[…] are related to gender. Our anatomy is sexually dimorphic – yet some individuals are born with ambiguous genitalia. Notice the photo that shows the range from a “normal” boy to a “normal” […]

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