Age: 43
Occupation: Psychologist, University of California at San Diego
It's better to detect a disease sooner rather than later, but if that condition is a developmental disorder like autism, which strikes at very young ages, how can you spot the first signs? Pierce is developing screening tests to identify children at risk of developing autism when they are as young as 1 year old. (Most symptoms don't appear until age 2.) Her tests could help parents and doctors intervene early enough to avoid some of the disorder's most severe behavioral and cognitive problems.