Friday, June 4, 2010

Better Know Your Hermaphrodites

We all began this world as girls. The male genome differs from the female in the key fact of extra genetic material (well, extra expressed, less overall). A tiny Y chromosome, with a tinier gene known as SRY, informs the masculine fetus that the uterus and vagina they were developing are of no use, instead growing a second set of tubes (our former embryonic kidney), into a new, more standing up to urinate appropriate set of equipment. This duct, known in medical circles as the appropriately manly "wolffian duct," is activated by Testosterone, the overproduction of which is the definitive physiological trait of manhood. The external genitalia, the organ on which we of the far less fair sex place so much importance, is derived from signals using dihydroxytestosterone (DHT), otherwise known as the hormone that makes you go bald and get a swollen prostate (about 40-60 years down the road). At the same time, mullerian inhibiting factors are obliterating your once promising female genital tract, obliterating the paramesonephros.

But remove these signals, and we develop along the baseline, into someone that is almost a women. You see, we still express baseline levels of estrogen, so in the absence The signals can be broken in several different places, causing several different outcomes.

One breakage can be in the production of testosterone. A 17-alpha hydroxylase deficiency we can't manufacture the copious testosterone needed to inform our bodies what to do, and without the testosterone, there is no DHT. Depending on the damage, the XY fetus would develop as either a partial hermaphrodite (small penis, blind vaginal pouch), or as a women. This all depends on the degree of insufficiency, a sliding scale of gender.

A 5-alpha reductase deficiency will block the production of DHT, leading to an entirely male form, except for that ego and gender defining locus, the genitalia. Ambiguous at best, these infants force the doctor to say "I'm not sure" when announcing the sex. They are male, of course, but will need hormone shots, and possibly a bit of surgery, to function normally.

Androgen insensitivity implies a child whose cells blithely ignore the flood of testosterone, developing quitely into almost female. These children are sterile, presenting with complete lack of internal genitalia. The testicles do develop marginally, and have a distinct tendency to get stuck in the inguinal canal (the site of the hernia), where they also need to be removed to prevent any cancerous development. They are the simplest, because genome aside, they are essentially girls. Typically tall, slender girls, with symmetrical bodies, larger than average breasts, and no body hair. (think about that next time you look at a model)

The true hermaphrodite, the fully formed penis and vagina, is the rarest of breeds. In class, one day, discussing this phenomenon, we heard a professor utter the most odd of screeds: "Its easier to dig a hole then build a pole." These children are almost always forced into feminity, regardless of their intention, because thats the way our society directs the outcome.

Masculinity is a narrow thing. Perhaps we shouldn't take it so seriously?

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