Some of the most fascinating theories of what causes autism focus on the womb. There’s the idea that the disorder stems from maternal flu exposure during pregnancy, for example, or from too much prenatal testosterone, or from not enough prenatal folate.The trouble is, for now these hypotheses leave us with more questions than answers. At what stage of pregnancy does a flu infection confer the most risk? Do these prenatal conditions lead to a range of developmental disorders, or specifically autism? How much does genetic predisposition come into play?On Tuesday, researchers from four U.S. institutions launched a huge study that sets out to unpack some of this complexity. The Early Autism Risk Longitudinal Investigation (EARLI) will follow 1,200 pregnant women who already have a child with autism.Read more at...SFARI, June 2009.