The Buffalo Bills shattered a major glass ceiling in sports on Wednesday by hiring the NFL's first full-time female assistant coach.

Kathryn Smith will serve as the organization's quality control coach for special teams. Smith used to work as Bills coach Rex Ryan's administrative assistant; she also worked with Ryan while he was with the New York Jets.

Shattering the glass ceiling. Congrats, Kathryn! More on the Bills new special teams coach: https://t.co/UOXRXdtBWQ pic.twitter.com/K0fVtdcc8T — Buffalo Bills (@buffalobills) January 21, 2016

The Bills have shattered glass ceilings for the NFL before — the team hired professional football's first female scout in 1986. The Bills are also one of the few football franchises with a female owner.

Ryan said he consulted with Bruce Arians of the Arizona Cardinals to see how he handled making this kind of history this summer. Arians hired Jen Welter as the first woman to hold any kind of coaching position in the NFL, an intern coaching linebackers during the summer preseason.

As the New York Daily News points out, it's an encouraging sign for Smith's transition that Bills offensive lineman Richie Incognito, who is "known for being a bully in the clubhouse," tweeted his enthusiastic support for Smith:

Congrats Kathryn!! I know you will do a great job. https://t.co/DWpWQJAtV5 — Richie Incognito (@68INCOGNITO) January 21, 2016

What does a "quality control coach" actually do?

It's actually more data analysis than "coaching" as it's traditionally thought of, according to the sports blog Mile High Report. But it's hugely valuable data analysis that helps contemporary coaches get the edge on their opponents, and it's a useful learning tool for an assistant coach who wants to advance:

In no time they absorb the ins and outs of the chess match known as football and the ingenious distinctions between wins and losses. They also pickup how Pro teams organize their practices and their off-season, weight training and conditioning programs. Having access to the scouting, all the video, the personnel departments and the front office, the Quality Control Coach might be the best on the job training for anyone aspiring to become an NFL Head Coach.

In other words, this position could conceivably help Smith move her way up the ranks to higher-level coaching positions if that's what she wants.

And quality control coaches do get to do some on-the-field coaching, mostly for the "scout" team in practices.

Men's sports are slowly incorporating more women

The NBA is ahead of the NFL in terms of gender inclusion, which makes sense since women are a much stronger presence in basketball thanks to the WNBA. Becky Hammon became the second woman assistant coach in the NBA in 2014, and some speculate that her success with the San Antonio Spurs could eventually propel her to be the league's first female head coach.

Women professional football players are basically unheard of, and last year the NFL was given a C+ on its gender diversity in hiring by the Institute for Diversity and Ethics in Sport. That was actually an improvement after the Ray Rice assault case caused the league to get more aggressive in its outreach to women.

Professional sports in general, and football in particular, are hugely male-dominated enterprises. Even the US's world champion women's soccer team gets treated like an afterthought when compared with the worse-performing men's team. So any significant steps forward, like the one the Bills just took, are a big deal for women in sports and women in general.