The seeds of the Mailman Center for Child Development were sown on a tennis court during a match more 50 years ago, a conversation between a U.S. president’s sister and the director of a university pediatric department about how best to serve special needs children.

They both knew something about that world: Eunice Kennedy Shriver’s sister, Rosemary, was developmentally disabled and Robert Cooke, a pediatrician and department head at Johns Hopkins University had two severely disabled daughters. At a time when most severely disabled children were referred to as “mentally retarded” and often consigned to institutions, Shriver, her husband Sargent and Cooke believed the best way to change lives was through research and equipping those on the frontlines with the professional training and tools.

That conversation, in early 1963, was a game changer in the way the nation treated its youngest and most needy citizens, the first significant step toward opening 11 academically affiliated clinical and training facilities in the United States, including the University of Miami Miller School of Medicine’s Mailman Center. Shriver was even present when the doors of Miami’s gray, nine-story building opened on the Jackson Memorial Medical Center campus in 1971.

“Our core mission has not changed, in that we are trying to learn and do as much as possible to help our children with disabilities,’’ said Daniel Armstrong, director of the center. “We are trying to help them live full lives and grow into independence.’’

Built upon the premise that “different” is about possibilities rather than limitations, the Mailman Center – the first of its kind in the nation – would become a part of national discourse about the care of special needs children and help shape public health policies. It opened with the assistance of a federal grant, the Kennedy Foundation and Abraham and Joseph Mailman, a pair of South Florida brothers and business executives who gave generously to healthcare and education causes.

Today, the center, operating on a $24 million annual budget, offers services to about 22,000 children a year through its early education programming, clinics and the high-profile inclusion school called the Debbie Institute – named after Abraham Mailman’s granddaughter, Debra Jean Segal, born with cerebral palsy. Over the decades, the focus has broadened to include the developmental risks of neo-natal newborns and children with serious chronic illnesses such as cancer. Currently, there are more than 70 active research projects and a sweeping set of programs ranging from an Early Steps intervention to a Fragile X clinic.

“The folks at the Mailman stand out for their willingness to work with and share information with others across the country and around the world,’’ said Margaret Nygren, CEO of the American Association on Intellectual and Developmental Disabilities, a Washington DC-based membership organization. “They are a national leader in the fields of clinical work, training and research.’’

Natalie Araneda, 21, born in Guatemala City, spent four years at the Debbie Institute learning to live with limited hearing.

“I came here to take a test when I was 1, after my parents realized I was not responding to the sound of their voices,’’ said Araneda, who wears a hearing aid. “There wasn’t really a place for me to go in my country for my level of hearing loss. We ended up moving here for me to be treated.’’