The stunning news that NBA center Jason Collins has come out as openly gay — and the reception it has received today – is only the latest sign of how fast societal barriers and prejudices are crumbling in the face of an astonishingly rapid cultural evolution when it comes to the civil rights of gay and lesbian Americans.

Collins made his poignant and moving coming out statement in a courageous essay for Sports Illustrated. In it, he discussed his reasons for doing so right at this moment. He was angry with himself for not marching in the 2012 Gay Pride Parade, and the Boston bombings reminded him how fleeting life is, so why not get it right sooner, rather than later? Collins also noted that seeing gay marriage cases being argued before the U.S. Supreme Court made keeping his silence increasingly unbearable: “nine jurists argued about my happiness, and my future. Here was my chance to be heard, and I couldn’t say a thing.”

This is a big, big day for gay rights — and for all of us. Collins is, as he put it himself, “the first openly gay athlete in a major team sport.”

“Men’s professional sports has been one of the last areas where gays have not had a presence,” prominent gay advocate Richard Socarides told me by phone. “Now that the first person has come forward, others will feel more comfortable doing so. Gay people will feel more comfortable pursuing careers in sports of their own. This is more evidence that more of society is opening up.”

It will also continue scrambling and challenging traditional conceptions of manhood, just as the debate over repealing Don’t Ask Don’t Tell did. “You can be macho and gay at the same time,” Socarides said. “Gay people, including gay athletes, come in all shapes and sizes and colors.”

That’s what I think Collins was getting at with his deceptively simple and straightforward first line:

I’m a 34-year-old NBA center. I’m black. And I’m gay.

The move is related to the repeal of DADT in another way: It, too, is challenging attitudes when it comes to camaraderie among gay and straight team members of the same gender — whether in sports or on the battlefield. Collins himself hinted at this when he wrote:

I’ve been asked how other players will respond to my announcement. The simple  answer is, I have no idea. I’m a pragmatist. I hope for the best, but plan for the worst. The biggest concern seems to be that gay players will behave  unprofessionally in the locker room. Believe me, I’ve taken plenty of showers in  12 seasons. My behavior wasn’t an issue before, and it won’t be one now. My conduct won’t change. I still abide by the adage, “What happens in the locker  room stays in the locker room.” I’m still a model of discretion. [...]

Look at what happened in the military when the Don’t Ask, Don’t Tell policy was  repealed. Critics of the repeal were sure that out military members would  devastate morale and destroy civilization. But a new study conducted by scholars  from every branch of the armed forces except the Coast Guard concluded that  “cohesion did not decline after the new policy of open service was put into  place. In fact, greater openness and honesty resulting from repeal seem to have  promoted increased understanding, respect and acceptance.”

As it happens, some sports figures are already expressing support. What about the fans? How will they react? When Jackie Robinson broke down the color barrier in Major League Baseball, he was subjected to endless torrents of abuse. Indeed,  one of the explicit conditions the Brooklyn Dodgers laid down was that he agree up front never to even respond to any of the nastiness and viciousness certain to be hurled his way. Perhaps in a reference to Robinson’s experience, Collins says simply: “I don’t mind if they heckle me. I’ve been booed before.”

But will Collins even be booed? Socarides predicts: “The fans are going to be very welcoming. We are much further along as a society in terms of accepting gay sexual orientation than we were as a society in accepting color differences when Jackie Robinson came forward.”

Jackie Robinson was black. Jason Collins, as he reminds us, is black and gay. Collins’ color, of course, is no longer an issue in organized sports. Soon enough, no longer will his sexual orientation. If it even proves to be one now.

Greg Sargent writes The Plum Line blog, a reported opinion blog with a liberal slant -- what you might call “opinionated reporting” from the left.