The 34-year-old Los Angeles native who helped lead Harvard-Westlake to two state championships in the 1990s with his twin brother, announced his sexual orientation in the May 6 issue of Sports Illustrated.
"I wish I wasn't the kid in the classroom raising his hand and saying, 'I'm different,' " Collins wrote. "If I had my way, someone else would have already done this. Nobody has, which is why I'm raising my hand."
Collins is the first active athlete to come out as gay in professional basketball, baseball, football or hockey. Others have come out as gay after they've retired, but never when they may still have to be in the locker room with teammates.
"I've been asked how other players will respond to my announcement," Collins wrote in the magazine. "The simple answer is, I have no idea. ... I hope for the best, but plan for the worst."
Homosexuality in men's professional sports -- particularly in the NBA -- has only been a topic for the last few years. In 2007, former player John Amaechi was the first former player to come out.
In the last couple of years, the topic has come up in the