What a powerful kiss.

Three days after Michael Sam embraced his boyfriend in a loving caress in front of ESPN's cameras after the St. Louis Rams drafted him in the seventh round, America is still feeling the aftereffects.

On Monday, the 24-year-old Sam - the first openly gay player drafted into the NFL - saw his No. 10 Rams jersey outsell that of every other rookie, with the exception of Heisman Trophy-winner Johnny Manziel. He even beat out the first overall pick, Jadeveon Clowney.

Even singer Adam Levine tweeted to his five million followers: "Anyone criticizing Michael Sam for kissing the person that he loves passionately on the most exciting day of his life are wrong. Period."

But negative reactions to the emotional same-sex kiss between Sam and swimmer boyfriend Vito Cammisano also overflowed on Twitter. On Monday, Miami Dolphins defensive back Don Jones was fined and excused from team activities after tweeting "OMG" and "horrible" in response to the kiss. And social media remained on fire with kiss fatigue and disparaging comments.

Whatever the response, Sam was asserting his power to live his life on his terms: as a proud gay man who plays football and is in love with another man. In February, the first-team all-American and Associated Press defensive player of the year came out to the world, clearly risking not being drafted at all. (He was chosen 34th in the seventh round, the 249th pick overall, out of 256.)

The kiss was Chapter 2 of what could be seen as Sam's unapologetic form of bravery. Never mind that Sam is black and his boyfriend white.

"I think that moment solidified what it means to change, especially in a culture - in a football league - that invested in hyper-masculinity," said Ellen Staurowsky, professor in sports management at Drexel University. "This has interrupted how people relate to the NFL, and change is never easy. That is why you see this reaction."

David Leonard, associate professor in Washington State University's department of culture, gender and race studies, agrees. And he says, it furthers an ongoing discussion in the sports world about what's acceptable in the realm of emotion.

"The entire NFL enterprise is selling a reality show," Leonard said. "And that kiss, that image was something different. It was love. It was a celebration of emotion. But it wasn't what we are conditioned to see as normalized. So it threw things off."

Through that kiss, Sam also declared, Don't be surprised when I show up at functions with my boyfriend and I thank him after an amazing play to win a crucial game.

"Emotions are at the core of humanity," Leonard said. "Acceptance of them tells us who is afforded those rights."

Recent Temple University graduate Lucky Fischer was never a big NFL fan, but when he saw the news about the kiss Monday morning on his Instagram feed, he smiled.

"Oh, wow, this is great," said Fischer, 22. "I think as a young, black, gay male it is a good thing to see male athletes coming out. Too many of us are afraid of being who we are. He was embracing the moment. That's normal."

Sports is often a microcosm of how Americans feel about hard-to-broach topics, especially diversity in the workplace and interracial dating.

"It was as if people didn't see the interracial aspect of the relationship anymore and they zoned right into the gay aspect of it," said James Peterson, associate director of Africana Studies at Lehigh University. "I mean people used to say they weren't prejudiced because they didn't want to see interracial relationships. That logic didn't make any sense to me. The reality is we live in a free society. He can date who he wants to and it shouldn't be offensive to you. And if it is, you should keep those comments to yourself."

American sports lags in forcing change in the workplace, according to Malcolm Lazin, executive director of the Equality Forum, a national LGBT civil-rights organization based in Philadelphia.

On May 3, the Equality Forum awarded its International Role Model Award to the National Hockey League. Lazin said he also invited representatives from the NFL, MLB and the NBA. None of them attended.

These professional sports leagues "are not being proactive when it comes to diversity, and homophobia is an example of it," Lazin said. "In fact, it's been nurtured . . . the culture continues to go on unabated."

Hence the definition of manhood becomes an issue over and over again. Last year's hot topic: Miami Dolphins player Richie Incognito's alleged bullying of teammate Jonathan Martin.

"We are in a place of transition . . . in a process of redefining what the norm is," Lazin said. "When Jackie Robinson started playing baseball, that was a huge story and it was a hugely difficult place for him to work in. . . . Football is one of the last bastions of machismo."