Her sons--10 and 12--are both ADHD and for Stacey Boutwell, why is more than just a curiosity.

"They are going to have children, I hope," she says, "I don't know if they'll pass it on." She says if they do, if there are things they can do to ease the effects, she wants to know.

Both boys are among hundreds now involved in testing on causes of ADHD at MSU. Professor Joel Nigg heads the testing. He also authored a book on the topic.

The most recent finding: even government designated "healthy levels of lead" may be behind ADHD. Testing on 150 children shows lead levels not only are higher in kids with ADHD, but seem to coorelate to the severity of the disorder.

"Part of what this study shows is it's not just genes," Nigg says. He says he doesn't doubt a genetic cause for ADHD, but he wants to further study how a lead influence may connect with that genetic cause.

Lead, Professor Nigg says, is everywhere--water pipes, toys from China, paint, and dirt too. The government says less than 10 parts per million in blood is safe, but Nigg says those kids are the very ones he's found with ADHD.

He now doubts if a healthy level of lead is possible.

"We shouldn't say this is just an extremely active child. Let's tolerate it," Nigg says, "We should say let's prevent this injury so this child can achieve his full potential."

It's why the Boutwell boys are involved and why mom Stacey is racking her brain on the family's exposure. It may be too late for them, she says, but they're happy to lead on the issue of lead.