And so what I'm trying to make sure of is that when I put the pen up against the control box, the length of the pen exposed at each end is equal.

NPR: Memoir Offers an Inside Look at Autism

Although the reason is not yet understood, earlier studies have shown that finger-length ratios are a robust marker of how much of that hormone a baby has been exposed to in utero the more testosterone, the longer the ring finger.

ECONOMIST: Autism