The market for at-home drug testing has exploded, with more than 200 Internet sites hawking tests for parents to use on their kids, Newsweek reported April 10.

Parents like Mike Peterson welcome the tests; he found out his 15-year-old son was using cocaine, marijuana, and amphetamines after forcing him to take an at-home drug test. "He had a problem -- a genuine problem," Peterson said. "Thank God we caught it before he hit rock bottom."

The tests sell for $15-$25 each, and have received free marketing assistance from the White House's Office of National Drug Control Policy, which has been campaigning widely for the use of drug tests of students.

Many schools have resisted calls for random testing, but parents have been more responsive. Even school officials reluctant to take the lead in testing have encouraged parents to do so, including publicizing home drug tests in school and through take-home materials for parents.

For example, the St. James R-1 School District in Missouri had Mason Duchatschek, owner of testmyteen.com, present an informational session to parents and is seeking a $100,000 federal grant to provide test kits to parents.

Critics say that websites selling tests to parents sometimes fail to give proper instructions to users, resulting in faulty readings. Boosters say the tests are most effective in preventing teens who have not used drugs from starting.