this is a well done study done by the university of california with millions and millions of kids worth of data. what they found is a 40-year-old mom has a 51% higher chance of having a kid who later -- having a baby who later develops autism compared to that 25-year-old mom. so when you look at those numbers, you can understand why that looks scary. >> when you look at those numbers, my question is why? why is that? >> there's two sort of camps here about why this would be. one is a biological camp that says as we age our dna changes not in a good way and we pass those changes on to our babies. or for example the longer we're on this earth the more you're going to inhale chemicals and other things and pass those on to your baby. the other camp says this has nothing to do with our bodies, per se. what it is as older moms tend to be more educated moms, moms who go to college and graduate school tend to have babies later in life. there have been lots of studies