[AbiDrew85]

PAIS = Partial Androgen Insensitivity Syndrome

To some degree, their bodies don't respond to androgens like testosterone. I would be interested to know if these boys have fully-developed genitalia and if they are fertile.

As far as I recall, they are fully functional males, they just have a VERY "bad" case of gynemastasia (Is that the correct word?)

Yes. And a highly localized form of PAIS can cause that. And they would otherwise still be fully functioning male.

BTW... CAIS above, a clarification, they aren't fertile. They only have the EXTERNAL characteristics, all the male-ish equipment is still inside, just never develops, like, at all, but pumps out tons and tons of hormones. They'll actually have higher serum levels of T than ANYONE else. Their body just doesn't respond. Responds to the estrogens it winds up aromatising to though, thus the fully feminized externals.