Either he had a sex change when he was little, he's gay, or he's simply a girl and never told anyone... I prefer the last view, so here's the proof.

1. He wears excessive amounts of make-up... namely, PINK EYESHOW and loads of eyeliner. What a girl.
2. He wears fishnets on his arms. See the video for 'Lifestyles of The Rich and Famous'.
3. His physique is feminine. Those cheekbones! Those lips! His whole skinnyness...
4. He enjoys art and wanted to be a comic book artist. Most rock stars DON'T enjoy art. Interesting...
5. His tattoos are girly... elvish writing... cartoon characters... horseshoes... stars... flowers... God. Does he need to make it anymore obvious he's a girl?
6. Everyone thinks he's 'pretty'. Ha ha.
7. "I never really went out and played in the woods with a bunch of snakes under rocks. I was scared of snakes." Really macho, Billy. You wimp... in a cute way.
8. A CLASSIC Billy quote - "Let's all hold hands and run under the rainbow."
9. OK, so I'm running out of evidence... JUST LOOK AT THE MAN! I mean... girl...