Did you read that Dan Savage article about women's 'fluid sexuality?' He did some research, and apparently there's research from a major uni (I think it was Northwestern) that shows women of almost any persuasion can find both het and m/m interesting. But JB really was very androgynous when he was younger--I had a screencap of his old b&w promo pic, and my partner glanced over my shoulder and said, "Hey, she's kinda butch, but really cute." which was true, of course... except for the pronoun.
Now you're going to make me wonder about my sexual orientation, since I have had major or minor crushes, over the years, on Keanu, Brad, Johnny Depp, Johnny Cusack (omg yes), Orlando Bloom (well, okay, not in the elf wig though), and of course dear Jamie himself. Perhaps I am not as het as I thought I was... ;)