Are there women with XY chromosomes?

Question by: Jorge

As you may (or may not) know, we all have 2 sexual chromosomes, which determine our biological gender. Men have XY chromosomes (one “X” and one “Y”), and women have XX chromosomes (two “X”s).

However, there are some exceptions. 

Perhaps the most relevant condition is androgen insensitivity syndrome.

Believe it or not, I remember this topic not from med school but from a House episode (*beware spoiler).

In that episode, House sees a patient, a young woman, who is admitted to the hospital for double vision, aggressive behavior, and cataplexy (she cannot move but is conscious inside).

After a long episode with several U-turns (drug addiction, sexual abuse, PTSD…), the woman turns out to have a tumor, causing a paraneoplastic syndrome.

Where was the tumor? In her testicle.

How is that possible?

She was born a man. Nevertheless, when a male person has androgen insensitivity syndrome, their testosterone can’t make its usual effect.

Testosterone shapes men and gives them their facial features, and hair patterns, shapes their penis and scrotum, and helps their testicles descend.

In severe cases, testosterone cannot have any effect at all, so the person will develop as a woman outside. She won’t have any uterus or ovaries, though, because there is no estrogen to develop them. Instead, she will have some small testicles inside her abdomen, unable to descend to a scrotum that doesn’t exist.

Not all cases are severe, though. Some are mild, and the patient looks like a male with some light feminine traits.