Look back at United States institutions and their history of diversity. They all tried to stay homogenous, and all eventual crumbled to other genders, races and creeds.

It appears (finally) that the American institution that is the NFL is no different. The boys club, very slowly, is starting to welcome women who know football. Women like Jen Welter.

Eagles defensive lineman Vinny Curry, during OTAs back in June put it pretty straightforwardly. He said "[NFL locker rooms are] like having a guy's night and you want to bring your wife. No,-- it's a guys night."

In Arizona, Welter is being hired as an assistant coach, technically a coaching intern for training camp. But like Michael Sam before her in the NFL, and the NBA's Becky Hammon, if you know the game or can play it well, there is a place for you in it.

"Someone asked me yesterday, 'When are we going to have female coaches?'" Cardinals coach Bruce Arians told his team's website. "The minute they can prove they can make a player better, they'll be hired."

Well, Welter, who has played running back alongside men and also coached professionally with the Texas Revolution of the Champions Indoor Football league as a coach of linebackers and special teams, will help with inside linebackers in Arizona.

"Coaching is nothing more than teaching," Arians continued. "One thing I have learned from players is 'How are you going to make me better? If you can make me better, I don't care if you're the Green Hornet, I'll listen. I really believe she'll have a great opportunity with this internship through training camp to open some doors for her."

Welter is clearly a trailblazer, and a good showing in camp with the Cardinals could open doors not only for her but for women in football everywhere. A door already kicked open by the Hammon with the NBA's Spurs.

Hammon helped lead the Spurs to an NBA Summer League title, to much fanfare. But San Antonio's head coach Greg Popovich said while it was worth the fanfare, women's basketball coaches have been fantastic leaders in the sport for decades.

"You know, it became huge when we hired her, and now it's even bigger, because of the Summer League situation. But we didn't even think about that stuff," he said. "I hired her because she was in my coaches' meetings for a whole year because she was injured, and she's got opinions and solid notions about basketball."

In 1999 the US Women's soccer team won the World Cup, and made it cool to 'play like a girl.' Now, in 2015, it appears that mainstream sports are finally ready to let girls call the shots too.

It's about damn time.