A Barbie with Down syndrome is already selling out. Here's how kids with the genetic disorder are reacting.

Barbie may have started off as a tall, busty, blonde, but Mattel has created many iterations of the classic doll over the years. She has used a wheelchair, become curvier, and had a range of skin tones. Now, for the first time, Barbie has Down syndrome.

Kate Green's 9-year-old daughter, Lorelei, already has a large Barbie collection. When Green first showed her daughter, who has Down syndrome, the iconic doll's latest update — created in partnership from the National Down Syndrome Society (NDSS) — the young girl lit up.

"What? No way!" Lorelei gushed, her mother tells Yahoo Life. “Yay. Mommy .. look … mine.” According to Green, Lorelei is "really just now recognizing that she has Down syndrome," and "may not even notice [that the new Barbie has] Down syndrome right off the bat." But Green sees it as a step in the right direction in helping her daughter "take pride in herself."

"She sees a pretty doll and Lorelei knows she’s pretty too," she says.

Created as part of the Fashionistas line, the just-released Barbie with Down syndrome doll is part of Mattel's commitment to help "counter social stigma through play," says Lisa McKnight, executive vice president and global head of Barbie & Dolls. The toymaker sought out input from people with Down syndrome and the organization that represents their interest, the NDSS, on the doll's design and messaging.

"As a woman with Down syndrome, I was proud to contribute to these meetings with my other colleagues, offering guidance on the design and style of the Barbie doll,” Kayla McKeon, the manager of grassroots advocacy at NDSS, tells Yahoo Life. "I'm going to be so proud seeing this doll on shelves," she adds.

Based on input from NDSS, the new Barbie with Down syndrome includes “a single line in the doll’s palm, a body with a shorter frame, longer torso and low muscle tone, a new face sculpt, featuring a rounder shape, tinier ears and a flat nasal bridge,” McKnight tells Yahoo Life.

NDSS president and CEO Kandi Pickard adds that process was “purposeful with every design choice …from the new face and body sculpt to the accessories which feature colors and symbols that are associated with Down syndrome awareness.” Those accessories include a necklace with three chevrons representing the three copies of chromosome 21 that cause Down syndrome and leg braces that some people with Down syndrome wear to help them walk. The Barbie also wears a dress decorated with butterflies, a symbol of the Down syndrome community.

McKeon says she believes "that the impact will be huge for people with Down syndrome" like herself. Indeed, the reaction has been overwhelming. “To all the girls out there with Down syndrome, THIS IS US!!!” Grace Strobel, a model with Down syndrome, wrote on social media in response to the Barbie.

“This is the greatest ever!!" Strobel shared. "When I got this Barbie it made me so incredibly happy and so proud. Tears of joy because it shows that although we are all different we all belong! This brought so many emotions to my mom and I because now this is one step further to acceptance. To feel good about ourselves and who we are. Thank you Barbie for recognizing the importance of representation and inspiring the next generation.”

Meriah Nichols posted a video of her 13-year-old daughter Moxie, who has Down syndrome, reacting to the new Barbie. “Barbie has Down syndrome just like me!” Moxie says excitedly. “She was just thrilled that there is a Barbie with Down syndrome out there," Nichols tells Yahoo Life.

For Austin Carrigg, whose 8-year-old daughter Melanie also has Down syndrome, the new Barbie is long overdue.

“I appreciate so much that there is now a Barbie that is modeled after an individual with Down syndrome, but frankly the fanfare over it I just don’t understand," Carrigg says. "This should have become commonplace years ago. … Why aren’t all manufacturers of dolls creating toys that look like all of their consumers?”

Carrigg hopes Mattel will start producing a Barbie with Down syndrome in different skin tones so her daughter, who is Asian, can see herself better reflected in Barbie. She notes that while this is “a step in the right direction,” there still isn’t a doll that looks like Melanie.

McKeon says it’s not just people with Down syndrome who will benefit from the new Barbie. “Everyone should be playing with a Barbie doll with Down syndrome because kids and adults need to see the world in a different way. We are all diverse and the Barbie dolls that we play with should represent that. It’s going to be so meaningful for children with Down syndrome to have peers who play with a doll that represents them,” she tells Yahoo Life.

Nichols, who is deaf, also hopes that typically developing children will play with the new Barbie. “There have been dolls with hearing aids,” the mom notes. “On one hand, yay! Yes, representation! But on the other hand, I really want to see these types of dolls being played with by kids who do not have our respective disabilities. In other words, these dolls are for everyone, just like dolls with different skin colors can be played with and enjoyed by all kids.”

For now, the tricky part may be getting ahold of the Barbie, which is already sold out online, in the first place. Neither Green nor Nichols were able to find one in stock anywhere.

“I desperately searched how to find one," Green says. "I tried to order but they are sold out."

Wellness, parenting, body image and more: Get to know the who behind the hoo with Yahoo Life's newsletter. Sign up here.