(CNN) "I'm not paid to be a role model," former basketball star Charles Barkley once said, sparking a debate about whether athletes owe a debt to society beyond the playing field.
More than 20 years later, tennis world No. 1 Novak Djokovic wants to end that debate. He insists that sporting icons "absolutely" have responsibilities as role models -- and he's backing up his words with action.
"There are many athletes who maybe just don't realize to what extent, and how far, their voice goes," the 28-year-old told CNN's Open Court show in Belgrade. "That power can be used in a very positive way."
Djokovic and his wife Jelena are leading by example through the Novak Djokovic Foundation, established in Serbia to secure precious learning time for children six and under.
Having met while still at school, the couple tied the knot in 2014. One of the things that united them was a passion for charitable causes, with business graduate Jelena assuming duties as the foundation's director upon its inception in 2007.
Back then it was known as the Novak Fund, with a mission to help youths affected by Serbia's war-torn past.
"In Serbian history, the years between 1991 and 2001 are probably the 10 most difficult years that we have had as people. The consequences of the war are still felt many years after it finished," says Novak. He counts himself as one of the lucky few who was able to pursue his dreams -- even if he had to miss youth tournaments because his parents could not afford the travel.
"It made me hungrier for success and made me more balanced. I never lost that bond and connection to other people who have struggled and are still struggling," he says, adding that his exposure to the devastation in his homeland had created a desire to "do something when I have the spotlight."
In 2011 -- the year Djokovic first topped the rankings, winning three of that season's four grand slams -- UNICEF appointed him as an ambassador to help raise awareness of low preschool enrollment in Serbia.
A year later, his organization formally declared itself as a foundation with a mission to nurture the minds of children aged six and under who would otherwise have been left in the dark. It raised $1.4 million at its first benefit dinner in New York in 2012, and another £1.2 million ($1.7 million) in London the following year.
"Research has shown that if you don't stimulate the brain enough from zero to six years of age, you are missing out on an opportunity that will never come back to you, because the brain grows exponentially until you are six," explains Jelena, who estimates that half of Serbian children -- a number nearing 90,000 -- are deprived of that activity.
Pinpointing just one cause was a sensitive matter and also a political one, she explains.
"It was a very difficult choice, because there were so many people in need of help," she says. "We were receiving so many requests: 'Please help here, help there.'"
"We just didn't want to close our eyes and take a pick -- that just wasn't something that was attractive to us," adds Jelena, who explains that the couple used research done in the country to show which areas could be improved with a sustainable investment strategy.
Their focus on youth education did not please everyone, she admits.
"The decision to invest in early childhood education is not a popular one at all (in Serbia), because not many people see the benefits or the visible results in the short run," she explains, adding that the long-term process of establishing a youth education program was not a strong enough crowd-pleaser for politicians who are running for office every four or five years.
"That's why it wasn't a popular decision by the government, and that's why we took over the role as the investors and advocates for the early childhood development and education."
The birth of their son, Stefan, in 2014 only reinforced the importance of early education to the new parents.
"As a mother, I'm very passionate about this," Jelena enthuses. "I'm breathing and feeling all the pain that a lot of families are feeling.
"Both of us as parents are really passionate about giving a lot of opportunities to our child: we are reading a lot, we are exposing him to different stimulative environments," she adds, citing a curriculum influenced by The Institutes for the Achievement of Human Potential, a Philadelphia-based non-profit organization that is a pioneer in early child development.
"We are (implementing) the physical program, the intelligence program, the musical program and the languages program," she says.
It sounds like a lot to take in for a baby still only 16 months old -- but these are life-shaping moments, the couple insists.
"Children want more knowledge; they want more information and they want more facts," Novak says, leading the conversation back to the responsibility of being a good role model.
"If they like you -- for one reason or another -- they will follow you in every part of your life. Some people may look at that as a burden, but I look at it as a great privilege and a great opportunity to do something, and create a change that will be positive."
Even though Djokovic is well on his way to cementing his legacy as one of the greatest tennis players of all time he's still just dad at home, as Jelena acknowledges.
"I feel very sad, because my husband is a great role model but my son will never look at him that way -- he only knows him as daddy," she says with a knowing smile.
"We need to find another athlete who is a role model for my son."
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