DAVID WRIGHT, ABC NEWS CORRESPONDENT (voice-over): From the highest court in the land --
UNIDENTIFIED FEMALE: Tonight, landmark ruling. The Supreme Court redefines the modern American family.
WRIGHT (voice-over): -- to the most competitive court in the land.
STEPHANOPOULOS: You always knew you were gay? UNIDENTIFIED MALE: Yes. It's -- I sort of describe it as you know that the sky is blue but you keep telling yourself that it's red.
WRIGHT (voice-over): 2013 was a game changer. From the church and its new, more accepting pope and state after state after state legalizing gay marriage, 2013 broke the rainbow ceiling, the biggest year for gay and lesbian rights since the Stonewall riots 30 years ago.
WRIGHT: This has been a good year for the gay and lesbian community.
UNIDENTIFIED MALE: Yes, it has. It's funny to me because I've just come out and I'm kind of on the other side.
There it is.
WRIGHT (voice-over): Soccer star Robbie Rogers of the L.A. Galaxy is living that change in real time. Earlier this year, he posted a courageous personal note to his blog and became the first professional soccer player in history to tell his fans that he was gay.
ROGERS: Yes, I was really, really nervous. And then instantly after I sent it, I felt so much lighter.
WRIGHT (voice-over): Plenty of other professional athletes have come out after they had already left their respective sports.
But active players, still in their prime, openly gay? Unheard of in American sports. At least on a professional level, until this year. Not only did Rogers come in, so did veteran NBA center Jason Collins, who sat down with George.
STEPHANOPOULOS: Martina Navratilova said that this is going to save some kids' lives.
COLLINS: You know, I look at her as one of my heroes. Hopefully going forward, I can be someone else's role model.
WRIGHT (voice-over): Collins made the cover of "Sports Illustrated," where he disclosed that he chose the number 98 to honor Matthew Shepard, a young gay man murdered in 1998 in a hate crime.
STEPHANOPOULOS: What do you say to the 12-year-old boy who's out there practicing right now, wants to be a pro ballplayer and happens to be gay?
COLLINS: It doesn't matter that you're gay, but the key thing is that it's about basketball.
WRIGHT: Pro sports is of course high pressure, high profile, almost stereotypically manly, but so is another realm of American life that saw a huge shift in attitudes in 2013, the U.S. military, having already dropped its longstanding ban on gay and lesbian service, this year it extended full benefits to same-sex spouses. Astonishingly, the U.S. military is now more open than U.S. professional sports.
If the military can change, surely the locker room can change.
ROGERS: Yeah, you would think so.
WRIGHT: For the armed services, that final shift toward full acceptance of gays and lesbians, came as an immediate consequence of the U.S. Supreme Court ruling this year in a landmark case brought by Edie Windsor who spoke with Diane Sawyer.
SAWYER: When you see the words, though, Edie Windsor versus the United States of America...
EDIE WINDSOR, ACLU: When I first saw it, I was terrified. I was just -- I thought what have I done? And then I gradually understood that the government wasn't going to be personally mad at me.
WRIGHT: Windsor and her partner of 42 years got married in Canada in 2007 and sued to have their marriage recognized in their own country. It took the U.S. Supreme Court to make it happen.