PORTLAND, Ore. -- The numbers are startling. A recent study reveals one in ten Oregon eighth graders has smoked marijuana in the last 30 days.

Your children tell you they don't do drugs, but how do you know? Nationally parents are spending millions of dollars on at home drug test kits because they want to know for sure. Despite warnings from governmental agencies and counselors, sales of these test kits are soaring into the tens of millions every year.

Tammy Hernandez, a Portland area Mother of two, talks with her children about everything, including drugs. Their relationship is based on trust and respect. Her children don't do drugs, and she says she'd buy a test kit only as a last resort.

"I would hate to think about it, right now I think I'm never going to have to do that," she said.

But Hernandez does know a parent who used the test to clear up a misunderstanding about his child's drug use. "It was an excellent example of using it to put you at ease."

Many parents are doing just that. Since the FDA okayed at home drug test kits a decade ago, millions of parents have purchased them. Tests claim to detect both illegal and prescription drugs. Directions walk you through the "at home" urine test for "immediate results," or you may mail the sample to a testing lab.

"It's scary when you think your kid is in danger!" Emily Moser of Oregon Partnership helps parents by creating drug prevention programs. She says recent drug use numbers may be daunting, but adds the tests are not part of drug prevention. "It's a gotcha." She says "scaring your child every time he goes out, like this is something that's hanging over his head, is counter-intuitive to the trust-building we believe helps build that positive family relationship."

Several governmental agencies also recommend parents not use the at home drug test kits. The American Academy of Pediatrics warns about the possibility of 'false positives'. The While House Office of National Drug Control Policy advises parents not to test for drugs at home, instead it advises you seek a doctor's help.

Moser advises parents to build close relationships with their children. "What we do know is that parents are the number one influence on children who don't use drugs and alcohol, because they want the trust and respect of their parents."

She says bottom line, get involved in your child's life. Hernandez is an example of that. "We talk about drugs a lot, about how to stand up for yourself and not bend to peer pressure."

For more information about drug prevention, please visit this Web site.