(CNN) -- McKenna Pope's 4-year-old brother wanted an Easy-Bake oven for months and she was more than happy to get it for him. She wants him to know it's OK for boys to enjoy baking cookies.
But she's worried that toy makers are sending boys a different message. The 13-year-old reached this conclusion last week during a shopping trip with her parents. They searched the shelves for an Easy-Bake Ultimate Oven and found pink and purple boxes that show only girls using the kid-friendly appliance.
They decided not to buy it because they thought the packaging would make him feel like he was playing with a "girl's toy" he wouldn't want. Still, McKenna decided to take it up as a cause and launched a petition asking Hasbro to feature boys in the packaging of Easy-Bake Ultimate Ovens.
"I feel that this sends a clear message: women cook, men work," Pope wrote in her Change.org petition, which has earned more than 30,000 signatures since it went up Friday night. "I want my brother to know that it's not 'wrong' for him to want to be a chef, that it's okay to go against what society believes to be appropriate."
With more people shopping for children's toys during the holiday season, McKenna and others are reviving debate over the effects of gender-biased toy marketing in a year that has seen intense discussion on the issue and even some progress.
It's easier for girls to play across gender lines, said McKenna, who spoke from experience. When she played with Nerf guns, people called her a tomboy, at worst, she said. But she has seen male classmates endure harsher name-calling for playing with dolls.
"I'm sure there are a lot of kids out there like my brother who want Easy-Bake ovens but don't ask for them because they're told they're not supposed to want them," she said. "There's a lot toys specifically marketed towards boys and girls, but guys need to learn to cook and take care of children, too."
Hasbro did not respond to a request for comment.
Not everyone believes children should play across gender lines. In a previous CNN story on the topic, some commenters said that allowing children boys to play with dolls or other toys typically associated with girls could make them targets of bullies. Others suggested that some color-coded marketing works and that selling pink LEGO or science kits packaged in purple attracts girls to toys that they might shy away from otherwise.
Toys come in different colors based on feedback from consumers and retailers, said a spokeswoman for the Toy Industry Association, a non-profit trade association that represents businesses involved in the creation and marketing of toys.
"Toy companies are basically businesses that respond to consumer requests," spokeswoman Adrienne Appell said. "If there's a market to explore, a company is going to want to put their marketing efforts behind products that families are going to buy."
Comments on the petition echoed McKenna's views about how the packaging and marketing might enforce gender stereotypes. Some parents, including men, agreed with her statement that boys benefit from playing with kid-friendly appliances and other toys typically associated with girls.
"I loved my Easy-Bake oven when I was a boy and I love cooking today. All boys should have access to the kitchen. And it's never too early to let them have that access," one commenter wrote.
"This goes for craft kits, too! My son (also loves cooking), has shown an interest in sewing, yet the kits out there are all geared toward girls. Cooking and sewing are basic life skills that all our children should learn ... especially when they show an interest," another commenter wrote.
Activists are heartened that a teen is speaking up on behalf of a sibling, rather than the usual advocates and opinion writers.
McKenna's voice lends credibility to the argument that traditional gender stereotypes are losing relevance among her generation, said Deborah Tolman, co-founder of SPARK, a nonprofit group that trains teens and young women to be media activists.
"People really listen when it comes from a young person or the actual consumer. It's different from adults making arguments in sophisticated words," Tolman said. "How can you ignore young people when they say they don't like what you're selling them and they want choices? It's pretty much a win-win situation for the advertiser and the consumer."
It's an issue close to SPARK, whose teen activists have orchestrated several campaigns in the past year to raise awareness of portrayals of women in media and popular culture. Last November, they launched a petition over LEGO's busty, pinkwashed "Friends" line asking the company to return to its gender-neutral approach to marketing. SPARK's efforts continued in 2012 by pressuring Seventeen and Teen Vogue to stop photoshopping models.
The fact that McKenna did it on her own -- as she and her mother claim -- shows that people her age are capable of scrutinizing media messages, said Dana Edell, executive director of SPARK.
"It matters most when it comes from them because they're the future leaders of the world who will be making decisions about marketing and advertising," Edell said. "So many people like to say, 'Who cares? Girls will always play with dolls and boys will always play with trucks and it doesn't matter.' So, it's encouraging to see someone who's not an adult stand up and say 'Wait a minute, actually, it does matter.' "
Toy marketing saw a shift this year when British store Harrod's re-opened its toy department organized by themes rather than gender.
More recently, Sweden's Top-Toy Group, a licensee of the Toys "R" Us brand, published a catalog featuring a girl aiming a toy gun and a boy styling hair with beauty accessories.
The gender-blind catalog prompted Carolyn Danckaert to start her own Change.org petition asking Toys "R" Us to follow suit in its catalogs and marketing materials in the United States. The company did not respond to a request for comment.
"People are recognizing that the divisions being created aren't necessary and it just makes more sense to be sorting toys thematically rather than by gender," said Danckaert, founder of "A Mighty Girl," an online marketplace for books and movies that feature females as main characters.
"We hear from parents all the time who see the value in allowing boys to play with baby dolls," she said. "A lot of people believe that it's desirable to encourage boys to become nurturers and develop the whole child, from analytical skills to the ability to empathize."
Since launching the petition, McKenna said she has learned a bit about scrutinizing ads.
"Now, whenever I see a toy commercial, I feel my mind automatically shooting to: 'Why are they marketing it this way?' " she said. "I can't help it. I wonder who this is being marketing to -- should they do it in a different way?"