After Under Armour launched its line of Star Wars shirts last week, customers quickly noticed something: There were no shirts for women and girls.

Under the "All Genders" line on its Web site's menu, the choices were initially only "men" and "boys" and featured items like Darth Vader compression shirts and Storm Trooper hoodies. On Twitter, fans erupted with complaints such as "you do realize this is the most lady empowering #StarWars yet, right?" and "Not sure you know it's 2015."

An Under Armour spokeswoman said the company has a "phased approach" and that women's and girls' shirts will be introduced in the coming weeks. But the flap was still a reminder of how conscious consumers have become about the way sci-fi entertainment and merchandise is marketed to women and girls, and how quickly things can go wrong if companies don't show they get it.

One woman who did get it—even six years ago—was Ashley Eckstein, an actress who played the voice of Ashoka Tano in the animated "Star Wars: The Clone Wars" movie and TV series. When she went looking for Star Wars apparel to wear at public appearances and sci-fi conventions, she had trouble finding it.

"I wanted merchandise to wear for me," Eckstein said in an interview with The Washington Post, noting that she had loved playing Star Wars with her siblings as a child and always wanted to be R2-D2, not Princess Leia. "But I scoured the Internet, and I came up empty-handed."

Eckstein, who is married to the retired St. Louis Cardinals MVP David Eckstein, was also inspired by the team apparel designed for female sports fans by Alyssa Milano's company, Touch. "I thought, someone's got to do this for female sci-fi and fantasy fans!" Eckstein said. "We were an underserved fan base."

Eckstein did her own research, learning that attendance at the biggest science fiction and fantasy conventions like Comic Con and Star Wars Celebration was 45 percent women. In 2009, she approached Lucasfilm to request a license for apparel designed specifically for women and girls.

Despite her turn as a Jedi, they turned her down—twice—until she paired up with a business partner, The Araca Group, which specializes in entertainment merchandising. She was granted a license, but only for sales at conventions and on her Web site. While initially restrictive, Eckstein says it forced her to grow her company, Her Universe, through grassroots measures by nurturing an online community of geekanistas. It also kept her from making costly, high-stakes retail mistakes.

"If you go into retail and fail, you don’t get a second chance," she said. "From day one we knew we had to have a merchandise part and a community part, and that was almost more important to me. Through my research I found female fans were being bullied, and often times online they would pretend to be men," she said, noting she wanted to create a "safe environment" for them.

Five years later, Eckstein oversees a growing business, which she says will do just shy of $10 million in sales this year, a number she expects will double next year. Her licenses now include not only Star Wars but Marvel, Transformers, Star Trek and others, selling apparel and accessories that range from basic graphic T-shirts and skirts printed with light sabers to Captain Picard cardigans and Darth Vader mask earrings.

Specialty retail partners now include Hot Topic and HSN, and she just began selling Star Wars apparel year round at Disney theme park locations, rather than just during special events. In October, Eckstein announced she was branching into publishing, planning to publish science fiction and fantasy writers that have an empowering message and a female protagonist.

Lucasfilm has taken notice. At a recent appearance at the Fortune Most Powerful Women conference, president Kathleen Kennedy mentioned Her Universe, saying Eckstein was doing an "unbelievable business" and that she had worn one of Eckstein's t-shirts at a convention. "It just shows that when anybody steps out and does something of quality, they find there are plenty of women and young girls who are just as interested as the boys," Kennedy told the audience.

Eckstein, of course, will have plenty of company as the Star Wars merchandising juggernaut continues to steamroll its way across America's retailers. Creating toys and apparel for both genders has been a focus of Disney and Lucasfilm with the new film, Kennedy said in her Fortune interview.

"There were a lot of companies that were in place who frankly didn’t initially feel that Star Wars was for girls," she said, also noting that having a main female character in the upcoming film was one of the first things she and director J.J. Abrams discussed. "We were all looking at this situation saying, 'No, with Star Wars we have to change this. We have to make sure that we create products that are, in a sense, appealing to both boys and girls.' "

And so it's not terribly surprising that we're seeing a girl with a light saber and her nostalgic, force-loving father in Toys 'R Us TV ads, as well as Cover Girl selling limited edition Star Wars-branded mascara (featuring quotes like "Luminous beings are we"). And while Jedi and Chewbacca T-shirts for women may have been hard to come by six years ago, they might soon be harder to avoid than to find.

Eckstein says that she has competitors who have copied her, and that she hopes to set Her Universe apart from the onslaught of other merchandise with the company's online community. The company has an active social-media presence that features a "fangirl" of the day, as well as a blog that gives advice to girls who feel bullied by their geeky preferences. 

At the same time, she's glad to see more attention being paid to sci-fi merchandise that might appeal to girls. "All we've ever wanted was just to be treated equally. My goal has always been to walk into a store and have an equal amount of products for boys and girls," Eckstein said. "Change is happening, and that's because the fans are asking for it." 

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