The pseudohermaphradatism House referred to was most likely an intersex condition called Androgen insensitivity syndrome. The presence of ovaries/other female genitalia seems to depend on the type of genital masculinization, although there never is a uterus present so I'm not sure how Wilson didn't see that when he looked for cancer.

I don't think Cuddy (or the writers) really understand how the placebo effect works. Just because a placebo helped with Houses pain, that doesn't mean his pain is psychological at all (even though it probably is partly - at least the recent flare up after Stacey left). The placebo effect will work on real physiological as well as psychological pain, so she proved nothing.