Radha Rangarajan loves Moana and Elmo, the playground and the “Pout-Pout Fish” book.
Like most 2-year-olds, she speaks in two-to-three-word sentences. (“Go outside!” “Mama sit.”) She gives kisses to anyone who asks.
But Radha’s life is far from normal. She can’t walk without assistance. Her health will probably deteriorate rapidly in coming...