34-year-old pro basketball Jason Collins came out as gay on Monday in a column for Sports Illustrated, becoming the first professional athlete in one of the country's preeminent sports leagues to do so.

"I wish I wasn't the kid in the classroom raising his hand and saying, 'I'm different,'" Collins said in the column, which SI posted online ahead of its May 6 publication date. "If I had my way, someone else would have already done this. Nobody has, which is why I'm raising my hand."

Collins, a free agent and 12-year veteran of the National Basketball Association, said in the piece that he dated women and was engaged to be married earlier in his life, but that he began thinking of coming out in public during the NBA labor dispute that truncated the 2011-12 season. He also said it was "unbearable" hearing the Supreme Court hear arguments regarding marriage equality in March 2013.

"Here was my chance to be heard, and I couldn't say a thing," he wrote. "I didn't want to answer questions and draw attention to myself. Not while I was still playing."

After sharing his sexuality with family members, he wrote, he decided to go public in 2012 after Massachusetts state Rep. Joe Kennedy (D), his friend and former college roommate, told him he had marched in Boston's Gay Pride Parade.

"I was proud of him for participating but angry that as a closeted gay man I couldn't even cheer my straight friend on as a spectator," said Collins, who played for the Boston Celtics and the Washington Wizards during the 2012-13 campaign. "If I'd been questioned, I would have concocted half truths. What a shame to have to lie at a celebration of pride. I want to do the right thing and not hide anymore. I want to march for tolerance, acceptance and understanding. I want to take a stand and say, 'Me, too.'"

Collins also acknowledged statements by heterosexual athletes like Brendon Ayanbadejo and Chris Kluwe in support of marriage equality, as well as President Barack Obama's mention of the 1969 Stonewall riots during his second inauguration speech in January 2013, while saying he had no idea how his NBA colleagues would respond to the revelation. Two-time All-Star Baron Davis voiced support Monday morning on Twitter, saying that he was proud of Collins "for being real."

While Collins is the first active NBA player to come out, former pro center John Amaechi was the first major sport athlete to do so, after his retirement in 2007. Collins' announcement also comes just under a month after former Chicago Bulls and Los Angeles Lakers coach Phil Jackson said in a Huffington Post Live interview that asking whether the league should be more inclusive of gay players was "a ridiculous question."

"None of us have probably ever seen it in all our careers," Jackson said at the time. "There's no inclusiveness to be had. I've never run into it in all my career."

Collins, who has played for six teams during his career, seemingly alluded to Jackson's statement in his SI column, writing, "Some people insist they've never met a gay person. But Three Degrees of Jason Collins dictates that no NBA player can claim that anymore. Pro basketball is a family. And pretty much every family I know has a brother, sister or cousin who's gay. In the brotherhood of the NBA, I just happen to be the one who's out."

On Saturday, Nike announced it had signed a gay female pro basketball player, WNBA center Brittney Griner, to an endorsement deal, making her the first openly gay athlete to be sponsored by the shoe company. Outside of the realm of major team sports, tennis stars Billie Jean King and Martina Navratilova both came out in 1981, though King has said her disclosure was the result of a lawsuit filed against her by a former partner.

[Image via Wikipedia Commons]