Anthony K. Shriver and Timothy Shriver spoke out after Robert F. Kennedy Jr.'s derogatory remarks about autism in an open letter."People with autism can and will continue to date, hold jobs, marry, and pay taxes," his cousins wrote, referencing his commentsThe brothers said they penned the letter in hopes of "celebrating the gifts of people with autism," who "can and will continue to go to school, be great friends, join teams, and contribute to their communities." Days after making derogatory remarks about autism during his first press conference as the secretary of health and human services, Robert F. Kennedy Jr.'s cousins called out "slurs and statements that demean" those with autism in an open letter. "We have been reminded again and again that people with autism can and will continue to be wonderful children, brothers and sisters, and members of families," a joint letter from Best Buddies Founder & CEO, Anthony K. Shriver and his brother, Special Olympics International Chairman, Timothy Shriver (who signed as Timmy P. Shriver) posted on the nonprofit's website and Instagram account reads. The brothers said they penned the letter in hopes of "celebrating the gifts of people with autism," who "can and will continue to go to school, be great friends, join teams, and contribute to their communities." They then made a direct reference to Kennedy's previous remarks about children who are diagnosed with autism spectrum disorder, in which he said, "These are kids who will never pay taxes. They'll never hold a job. They'll never play baseball. They'll never write a poem. They'll never go out on a date. Many of them will never use a toilet unassisted." Kennedy said his comments in response to a new study by the Centers for Disease Control and Prevention (CDC) that found 3% of children in the U.S. have autism. "People with autism can and will continue to date, hold jobs, marry, and pay taxes," Anthony and Timothy said in their letter. Alluding further to Kennedy's remarks, which were called "hurtful misconceptions," the letter said, "Slurs and statements that demean, devalue, demonize and identify people with intellectual and developmental differences as hopeless are not only inaccurate but they are also deeply damaging to the hopes and dreams of millions of people who struggle for dignity every day." The brothers vowed to continue their efforts to show that "people with Autism and other forms of intellectual disabilities have gifts." As mentioned in the letter, Anthony and Timothy's family has "been active in the work of promoting the gifts and contributions of people with intellectual and developmental disabilities for more than half a century." Their sister, Maria Shriver, commented on the Instagram post. "Proud of both of you mummy would be happy you did this together proud of our family’s work in this space that you both continue carry on ❤️," she wrote. The Special Olympics were founded in 1968 by family matriarch Eunice Kennedy Shriver as a nod to her sister Rosemary Kennedy, who was born with intellectual challenges. "She could always draw on the sure conviction that Rosemary was a person who deserved the dignity, joy and opportunity that anyone else deserved," Tim Shriver Sr., Eunice's son, told PEOPLE in July 2021. Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories. On April 21, Dr. Jay Bhattacharya, the director of the National Institutes of Health, announced that the NIH will provide Kennedy with data from federal and commercial databases to carry out a new autism study. He is also launching a registry that will track Americans with autism.