This study was reassuring to me. My oldest child had MANY scans (read: one a day for 1 week, then once a week for a few weeks, then a few more for good measure), my middle child had 3 (1 at first prenate, 1 @ 14 weeks because we couldn't find a heartbeat, then the 20 week scan), and my baby had 1 (just the 18/20 week scan). My baby is uber hyper and my middle child is left handed; my oldest, exposed the most, seems to not have any of the "trademark" issues. I struggle with whether or not to get one scan this time, but I am reassured knowing that, despite what's generally circulating around crunchy crowds, there isn't too much scientific study backing up scans being so toxic. To be honest, there just aren't a lot of studies, period. But this longitudinal review of cases was very reassuring for me.