I am, so far as I know, the only one in my immediate family. And it's not a homophobic family, everyone's perfectly fine with it (hell, my Aunt once gave me a book of gay love poetry for my birthday), so if there were any others, I doubt they'd have a problem being open about it. Therefore, I conclude there are no others.
There was, apparently, a gay guy way back on my mother's side a few generations ago. He was married with four kids, disowned one of them when she had the temerity to get pregnant out of wedlock, threw the entire family into turmoil by demanding that everyone else disown her aswell, called down hellfire and brimstone upon this heinous sinner, and then left his wife for another man.