(MCT) -- CHICAGO - Mary Cate Lynch sat in her mother's arms before a class of fifth-graders at Oriole Park Elementary School. The 2-year-old can't speak many words yet, but she has mastered a bit of sign language.
"Mary Cate, what's your favorite sign?" asked her mother.
The blond-haired, blue-eyed child twisted a finger to her cheek and made the sign for - what else? - candy.
That made the fifth-graders in the classroom laugh.
It was a sweet moment of connection between the students and the little girl who - born with a rare genetic disorder that resulted in deformities in her hands, feet and face - has become a pint-sized ambassador for kindness. What began more than a year ago, with another child's unkind words on a neighborhood playground, has since become a mother-daughter crusade.
Over the past six months, the girl and her mom, Kerry Lynch, have visited more than two dozen schools and summer camps in an effort to help children see that Mary Cate is more than just how she looks.
The Lynch family's very personal campaign has gotten a big boost from the surging popularity of the middle-grade book "Wonder," written by R.J. Palacio. Since its publication in February 2012, the book has become a sensation, selling more than 1.5 million copies, building a dedicated fan base of children and adults and, so far, spending more than 80 weeks on The New York Times best-seller list.
Written in part from the perspective of a fifth-grader who has a facial deformity, "Wonder" has inspired an anti-bullying campaign called "Choose Kind" and prompted tens of thousands of children to take a pledge to be compassionate toward others. It also has made the Lynch family sought-after speakers on the local elementary school circuit. They are booking dates into 2015.
Kerry Lynch said she has been humbled by the requests that have poured in from schools. What's more, she and her husband, Chris, say they feel a responsibility to help parents teach their children about differences.
"If you don't have a family member or a friend who has a disability, it can be a hard thing to try to explain," said Kerry Lynch, 33. She maintains a blog and a Facebook page, My Mary Cate, and encourages other families to use the pictures posted there as a teaching tool.
"I tell people to use the pictures of Mary Cate's hands and feet to show how she's different," she said. "But also show pictures of her coloring, playing tea party and doing gymnastics so kids can see that she's more alike than she is different."
The sky was blue and the sun was shining on a beautiful day in March 2013 when Kerry and Mary Cate ventured to a park a few blocks from their home in Chicago's Beverly neighborhood.
Kerry was pushing Mary Cate in a swing when a little boy playing nearby blurted out: "What's wrong with that baby's face?"
Before Kerry could respond, the boy's mother - clearly mortified - whisked him out of the park.
All day long, the incident bothered Kerry. She knew children would ask questions. She felt it was important to answer those questions honestly. More than anything she had wanted to follow the boy's mother to tell her that it was all right and to introduce Mary Cate.
She posted a description of the incident on Facebook and was stunned to receive a flood of messages in response. Someone suggested that she bring Mary Cate for a visit to the neighborhood school. The students all lived nearby and were likely to encounter Mary Cate.
What better way to make an introduction?
A few weeks later, the Lynch family spent two hours at Christ the King School, visiting every classroom from kindergarten to 8th grade. The visit "eased our fears right away," Kerry Lynch recalled. "The students were wonderful, crowding around (Mary Cate) and wanting to say 'hi.'"
Kerry and Chris Lynch walked out of the school feeling the visit couldn't have gone much better. They didn't expect anything more, except perhaps to have made a few friends and allies. But when photos of Mary Cate's interactions with the students were posted on Facebook, the Lynch family found themselves fielding calls from schools across the Chicago area.
When those invitations began arriving, the family did not hesitate.
"If we can make her life an ounce easier, that's what we want to do," said Kerry Lynch. "If that means going to talk to kids and letting kids see her in person and seeing her goofiness and stubbornness, that's what we are going to do."
It was, in a way, a reversal for the family. After Mary Cate's birth, Kerry's first instinct was to hide her child to protect her from the world. Now Kerry knew the best thing to do was the exact opposite.
By then, in spring 2013, "Wonder" had become the No. 1 middle-grade book on the best-seller list.
A New York-based graphic designer named Raquel Jaramillo, whose pen name is R.J. Palacio, was inspired to write the book after her family visited an ice cream shop and found themselves sitting next to a girl with a facial deformity. Jaramillo's 3-year-old son burst into tears, and Jaramillo rushed her children away. In the scramble, she knocked over three chocolate milkshakes.
"Writing this book was somewhat of an atonement," Jaramillo said in a phone interview. "It was a moment I really regretted. I should have just turned to the little girl and maybe started up a conversation and shown my son, by example, that there was nothing to be afraid of."
That day, Jaramillo said, "I started thinking about what it must be like for that girl and her mom to have to face a world that doesn't know how to face you back."
When Jaramillo heard the song "Wonder," by Natalie Merchant, on the radio, the idea for the book was born.
"The words to that song resonated so deeply because of what had happened that day. It's a song about a child being born with some uniqueness that makes that child a wonder of God's creation. But it's a joyful and optimistic song. I thought, 'I'm going to write a book. It's going to be called 'Wonder.'"
In Chicago, as the book's popularity grew, Kerry Lynch heard recommendations from all corners. A friend gave her a copy, but Kerry couldn't bring herself to open it.
"I knew it was going to mirror a lot of our life and what we had ahead of us," Kerry Lynch said. "I wasn't sure I was prepared for that."
Then schools began calling to ask if she and Mary Cate would visit. The teachers inevitably asked if Kerry would also talk about "Wonder."
She started reading and couldn't put the book down.
The story begins as 10-year-old Auggie is about to enroll in school after years of being taught at home by his mother. The book's short, engaging chapters are written from the perspective of Auggie and the children around him, as they struggle over the course of a school year with friendship and acceptance.
Kerry Lynch sobbed through much of the book and finished it in two days. She immediately knew she wanted to incorporate it into her talks at schools. "I thought it was an incredible tool for teachers to be able to teach the kids about differences," she said.
In the bright classroom at Oriole Elementary, Kerry Lynch told the story of Mary Cate's life.
She explained, in simple terms, the shock and sorrow that she and her husband felt in the delivery room when they first learned that something was wrong. She spoke about Mary Cate's diagnosis with Apert syndrome, a rare genetic disorder. She talked about the surgeries Mary Cate underwent to separate her fingers and toes, which were fused at birth.
While Kerry spoke, Mary Cate played happily on the floor nearby, at turns drawing with a purple crayon, swiping through images on an iPad and eating Cheerios.
She speaks slowly because of the shape of her mouth, but so far she does not appear to have developmental delays, which can sometimes occur with Apert syndrome.
Standing before the class, Kerry Lynch played a short home video and then called for questions. "Ask me anything," she said. "Nothing will hurt my feelings."
The children wanted to know:
How did you feel when Mary Cate was born? "We cried a lot," said Kerry, her voice breaking with emotion. "But in the same breath, we were absolutely in love with her."
How do you handle people staring? "I usually try to break the ice. I say, 'My name is Kerry. This is my daughter Mary Cate.' I don't think they're being unkind. I think they're curious."
Why do you bring Mary Cate to schools? "Just to show you guys that it's OK to be different," she said.
But the most powerful part of the presentation was simply Mary Cate being Mary Cate. The toddler was stubborn (refusing, at one moment, to sign "thank you"), shy (hiding, at another moment, behind her mother's leg), affectionate (exclaiming "Da-da" and hugging her father when he entered the room) and adorable (offering others Cheerios and then playfully pulling the snack away).
By the end of the visit, the children in the classroom were smiling broadly. They sang "Ring around the Rosie" as Mary Cate spun happily in a circle, and they broke into applause as the song ended and Mary Cate plopped to the floor. Mary Cate then climbed onto a chair and triumphantly gave each student a high-five.
Afterward, Emma Suing, 11, had tears in her eyes. "Knowing how much (Mary Cate) has been through," she said. "It's really heart-touching that she can communicate and that I can talk to her. That's why I have happy tears."
Jessica Andreu, 11, said the visit had helped her and her classmates to learn "how to be kind and to stick up for each other," and to appreciate the fact that "everyone is different in their own way."
Before the Lynch family left for the day, Kerry summed up the lesson the family had shared. Treat people with disabilities just like you treat everyone else, she said. "If we run into you somewhere," Kerry said, "I hope you smile and just say, 'Oh, hi! That's Mary Cate!'"