Growing up in Massachusetts in the late 1980s and early '90s, there weren't as many opportunities for girls hockey, so Katie Guay played with the boys until ninth grade. She always tucked her hair under her helmet. "I did it so when I was going into the boards, I wasn't as easy of a target," says Guay, now 36.

After graduating from Brown University in 2005, Guay began a post-hockey career in officiating. Now when she's on the ice -- in stripes -- she keeps her ponytail visible, poking out from behind her helmet. That includes this past week when Guay was one of four women to call NHL prospect tournaments; it was first NHL-affiliated event that women have ever officiated.

"People do notice," says Guay, who was in Anaheim where the Avalanche, Kings, Sharks, Ducks, Golden Knights and Coyotes all sent their top prospects. "The hope is our skill won't differentiate us from the guys out there. At the end of the day, you want to go unnoticed, and hopefully the ponytail doesn't change people's perception of our performance."

Guay points to her own personal paradox: officials, inherently, like to be anonymous. If people don't notice them, that means they're doing their job well. But Guay is also proud of who she is and what she has achieved. She hopes her presence on the ice could inspire the next generation of women to try officiating when their playing careers are over.

"It's just been an issue of exposure," says Kelley Cooke, who refereed for the prospect tournament hosted by the Predators in Nashville. "Women didn't really think of officiating as an option. I didn't [when I was playing]. If you don't see women out there, you wouldn't really think about it."

The NHL is committed to maintaining a talented pool of potential officials, and that has meant expanding recruiting efforts.

"We need great people in hockey, great athletes from hockey, to get into officiating," says Stephen Walkom, the NHL's director of officiating. "If they happen to be women, that's great. We just need the right people."

The NBA and NFL both have female officials in their rotations. The MLB is close, with umpire Jen Pawol becoming the first female to work a spring training game in 2018. The NHL isn't quite there yet, but could be soon.

"Maybe we just haven't attracted the women athletes with great skating skill sets to try it, that's the reason," Walkom says. "It's just a matter of getting the great women athletes out there and trying it and loving to do it. I don't think you can put a timeline on it. But when the right person comes along, and they develop into a top prospect and work in the minor leagues and conquer each league along the way, then we'll have a woman officiating in the NHL. That will happen, it's just a matter of time."

Walkom, a former NHL official himself, has led two big recruiting efforts for officials in his time with the league. The first came after the 2004-05 lockout. "We were getting lots of complaints, at all levels, about what's going on and what we can do to improve the pool of officials," Walkom says. He began reaching out to a lot of Division 1 and CIS schools, asking coaches if any of their graduating players would have interest in trying the profession.

Coming out of the next lockout, in 2013, the NHL implemented a series of rules that made the game much faster. Walkom knew he would have to groom a new generation of officials that could keep up. The biggest criteria for a modern official are hockey IQ, strong skating and athleticism. (Consider, most NHL official work about three games a week; current referee Dan O'Rourke told me in 2018 that he burns about 1,000 calories in a game.) Naturally, former players are excellent candidates.

"I really believe that some of the best officials in the world, male or female, are sitting on benches right now across North America and Europe playing hockey," Walkom says. "One day, should they want to give back to the game in a way that appeals to them, officiating could be a place for them in the game."

Walkom is constantly recruiting and looking for the right talent; he even put in a pitch to Kendall Coyne Schofield after she amazed in her fastest skating demo at the 2019 NHL All-Star Weekend.

The NHL created the Exposure Combine for Officiating in 2014, which is held annually in Buffalo. Walkom's staff runs the event and they invite officials of all levels (including ones trying it for the first time) to run through a series of on- and off-ice drills -- similar testing the NHL puts its officials through.

In its first year, there was one female participant. The next few years, there were two. This past year, 11 women attended. Walkom's staff identified four standouts -- along with Gauy and Cooke are Kirsten Walsh and Kendall Hanley, both linesmen -- and assigned them to NHL prospect tournaments so they could get reps at a high level. All four played college hockey.

"It's been a great experience," Cooke says. "Here this weekend guys are out there to prove themselves and earn a spot [on the NHL roster], so the compete level is through the roof."

Walkom says that everyone who goes through the Exposure Combine enters the NHL's prospective pool database. "They'll be people we'll be keeping an eye on, and watching their development," Walkom says.

Cooke says over the past five years there has been a "drastic change" in the amount of women interested in officiating. "When I played in college [at Princeton from 2009-13] there really weren't many women doing my games," she says.

Last year, Cooke and Guay teamed up as part of the first all-female crew to work at the NCAA Women's Frozen Four. "Exposure is growing," Guay says. "The path is being created as we speak."

This coincides with an overall growth in women's hockey. Girls hockey is one of the fastest-growing sports in America. According to USA Hockey, there were a record 82,808 registered female hockey players in 2018-19, with increases across all age levels including a remarkable jump of nearly 8% in year-over-year registration at the 9- to 10-year-old range. Walkom, who has two daughters that play hockey, says the talent level has grown significantly

All four of the women got into officiating because they said after graduating college there weren't many professional opportunities, and they wanted to stay involved in the game.

Hanley graduated from SUNY Oswego in 2009 and got an internship at the Dallas zoo. She happened to be at a rink playing in a pickup game when she met another woman who was an official. "At that time I was wondering, 'What am I going to do with my life?'" Hanley says. "I had just finished playing at a high level and I didn't know what to do with myself. I'm so used to being in a team environment, a competitive environment and training every day, and I just listened to her when she told me what this was all about. I fell in love with it. It's kind of like playing. It's challenging and you want to get better at it every day."

Welsh graduated from Robert Morris University this past spring. She planned to stay in Pittsburgh and began looking for jobs in the oil industry. She landed upon officiating because of Walkom's recruiting. Walkom lives in Pittsburgh and called RMU assistant coach Logan Bittle asking if there were any talented ex-players who might be interested. "If I took a job in oil, it's not a bad route, but I would be starting from scratch," Welsh says. "In hockey, I have 20 years of experience, skating and hockey knowledge."

Welsh is the only of the four women who had no prior experience officiating. At the Exposure Combine, she had to be taught the basic things such as how to drop the puck and where she should be positioned. She thinks she will try pursuing a career in officiating.

"I don't want to be chosen because I'm female, I want to be chosen because I can officiate," she says. "In officiating, you don't need the size and strength to compete with the men. You need to learn how to conduct yourself professionally, and know all the rules, and once you can handle that, I don't know why there wouldn't be an NHL female official really soon. Why not, you know? There's a lot of amazing candidates."

Hanley, too, feels like the NHL is close.

"Being at these events, you can tell the NHL and other leagues are opening up and allowing opportunities for the best officials -- whether they are men or women," Hanley says. "Obviously the NHL will look for the best officials. If that happens to be a woman, I have no doubt they'll make that decision when they find that female and give her that opportunity. And I will absolutely be on a flight, or do anything I can to get to the arena, be part of that experience, and cheer her on."