Tens of millions of American sport fans live with health conditions that you cannot see -- conditions known as invisible, or nonapparent, disabilities.
These fans have diabetes, chronic pain, autism, lupus, deafness, low vision and so many other challenges. They also have undying love for their teams.
From twin boys with autism who love the Philadelphia Eagles to a lifelong Boston Red Sox fan with low vision, these are their stories -- and the changes they would like to see.