We are all Trans

[NOTE: I will return to my previous thread on the subject of prenatal diagnosis of disability shortly. But due to the topical nature of this subject, I thought I should publish it at this time.]
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Fetal genital tract. Image from Wikipedia Commons

We are all Trans

Ted Cruz and Pat McCrory may not want to hear this, but the human embryo starts out with two sets of reproductive structures: one male and one female. In fetuses that receive a Y chromosome (genetic makeup: 46 XY), the fetal gonads become testes (notice the term “bipotential gonads” in the diagram above), and begin cranking out male hormones (androgens) such as testosterone, that cause the phallus to enlarge, and a substance known as Anti-Mullerian Hormone (AMH), which forces the female genital structures (“Mullerian ducts” in the diagram) to regress . The opposite occurs in female (46 XX) fetuses: the gonads become ovaries and begin cranking out estrogen; female genital structures develop and male genital structures (“Wolffian ducts” in the diagram) are forced to regress.

In simple English, we all start out with the potential to go either way.

Every guy has a prostate gland, which (unfortunately) completely encircles his urethra (Not a shining example of intelligent design). As guys get older the prostate gland enlarges, compressing the urethra and making it harder to pass urine. Just ask any guy over 50, or eavesdrop in a Men’s Room and listen for the guy who produces only a few drops at a time, then stops, and restarts once more. But I digress… We were talking about sexuality, right? I mention Men’s Rooms primarily to remind male lawmakers that each of you is the proud owner of a prostate gland. And if you could take a look inside your prostate gland, you would find – get ready for this – a miniature UTERUS – the remnant of your Mullerian ducts that was destined to become your full-fledged uterus, but was shut down by AMH during fetal life. Don’t just take my word for it. You can look it up (And let’s not forget the obvious fact that men have breasts – another remnant of our gender equipotentiality. To the best of my knowledge, breasts serve no purpose in men – although they do carry risks. My first breast cancer patient in med school was a man. Talk about irony and bad luck.)

There is a genetic condition in which the tissues of genetically male (46XY) fetuses are unresponsive to AMH and testosterone. Thus, their male organs fail to develop (or develop only minimally), while their female organs continue to develop. As infants – and adults – these individuals look partially or entirely female (depending on the degree of insensitivity to AMH and testosterone). Some, in fact, look positively voluptuous – because their bodies respond purely to estrogen, and not at all to testosterone. This condition used to be called “Testicular Feminization Syndrome” but is now referred to as “Androgen Insensitivity Syndrome”. Many of these individuals come to medical attention when they present for evaluation of infertility. Even though their external equipment is female, and they identify as female, their gonads (which reside in the abdomen, not a scrotum) are still testes, and they do not make eggs. (In fact, abdominal testes need to be removed because of the risk of cancer, and then the individual needs hormone replacement therapy). Can you imagine being told, at age 25, that your external physical characteristics and your genetic makeup do not match? If we go by their chromosomes, they are male. If we go by their physical appearances, they are female – often stunningly so. (There is a cottage industry dedicated to speculating which famous female movie stars and glamor models are genetically male.)

Now let’s consider another set of disorders, that go by the umbrella term congenital adrenal hyperplasia – CAH . Normally, the adrenal glands pump out a slew of hormones to regulate all kinds of stuff. Many of these hormones start from the same precursor molecule: cholesterol – and are converted by a series of steps into the different end products. Sometimes, however, due to genetic blockage of the metabolic pathway, the body cannot make the needed end products – so the output gets shunted over to an intermediary product called DHEA. DHEA has masculinizing properties, like testosterone. So if a female fetus inherits one of these disorders, her external genitalia may become “masculinized” due to the increased levels of DHEA (not from her gonads, which are ovaries, but from her adrenal glands) – sometimes to the point where her clitoris grows to be as large as a penis. “It’s a boy!” the Delivery Room Nurse announces grandly – but it’s not true. (Remember the Bearded Lady at the carnival? Think CAH. Or its metabolic distant cousin, Polycystic Ovary Syndrome, also due to androgen excess in females.)

So there are genetic males with the external apparatus of females, and genetic females with the external apparatus of males. You may say: “God does not make mistakes!” But delivery room nurses do!

Finally, just as there are receptor sites for sex hormones in the fetal genital tract, there receptor sites for the sex hormones in the fetal brain. Behavioral effects are harder to pin down than anatomic changes, but there’s no question that sex hormones “wire” the brain in all sorts of ways – including gender identity (what you think of yourself “as”) and sexual orientation (who you find yourself attracted “to”). Just as there are clear examples of a discrepancy between genetic makeup and physical equipment, there are also discrepancies between gender identity or sexual orientation and physical equipment. These discrepancies are a matter biology, not “lifestyle choice.” If you are 46XY and straight, ask yourself: Did you wake up one day and decide “Hey, I think I’ll be straight,” or “I think I’ll be a boy”? Of course not. You knew what you were without having to decide. Well, as hard as it may be for you to believe, the same is true for most other people as well, regardless of their particular combination of equipment, gender identity, and sexual orientation. The only “choice” some people make is whether to live their lives in secret, for fear of reprisals from the rest of society, or whether to be brave enough to be true to who they really are.

So, all you guys (Pat, Ted, I’m talking to you): Next time you’re in the john emptying your bladder, think of your little uterus. Or when you’re shaving, take a close look at your nipples. Then remember: One way or another, we are all Trans.

James Coplan, MD is an Internationally recognized clinician, author, and public speaker in the fields of early child development, early language development and autistic spectrum disorders. Join Dr. Coplan on Facebook and Twitter. Have a question for Dr. Coplan? Ask the doctor.