It's really a bunch of women who figured out how to expand the size of their clit. With lots of weights, pressure and probably drugs.
Yeah, as the URL says, it's a result of steroid usage.
There's also hermaphrodites but those are in very small numbers, small enough to be an anomaly.
While I do believe transgenderism is a legitimate thing, I don't believe we can call it being transgendered. I think it's part of body dysmorphia disorder mixed with gender identity disorder, but I don't know much about that.