DENVER (CBS4) – One of the most popular video game franchises in America now includes female soldiers for the first time.

The latest installment of “Call of Duty” has sold more than a billion copies to retail stores in just a week. The game has been around for about 10 years and always featured only male avatars. But some say what might look like a good thing for women may actually be opening the door to online abuse.

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Self-described girl gamer Margaret Moore has been playing online games for years. After hearing of “Call of Duty’s” introduction of female characters, she wondered how they’d be portrayed.

“In games most females don’t wear clothes,” she said men and boys would say.

She also wondered about the reaction among the game’s dominant male base.

“That was my big worry.”

Seeing that the female avatars are dressed similarly to the male characters was a relief.

“At first I started off with the girly ones, but then I realized the gory ones are the best ones,” Moore said.

The online abuse is a different story.

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“(They say) ‘Girls can’t game, they can’t play this game,’ “ she said.

After just a week of gameplay online comments range from, “It feels weird shooting a girl,” to, “I expect online harassment to increase by a million percent.”

The issue even came up this week in one of Dr. Pavithra Prassad’s classes at the University of Denver when the professor asked for the reaction of male players.

“This virtual shift to a more equal gender representation is a complicated one,” Prassad said. “And how uncomfortable it was for them to stab or shoot a female character.”

Prassad says it’s a move in the right direction, but the female characters are still masculinized and the fight isn’t over.

“When women enter that sphere and want to participate on the same level as men they encounter a lot of resistance,” she said.

As for gamers like Moore, despite what flak she may or may not get in gameplay, she plans to now use a female player, and keep on gaming.

“Because of this female avatar being made, more women are going to get into it,” Moore said.

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CBS4 got a response from the maker of the “Call of Duty” franchise as to why they decided to include female characters after 10 years. They said it’s due to feedback from the community and requests to customize all characters — male or female.