But most schools cannot afford the costly tests for detecting the illegal bodybuilding drugs. Even those that test for marijuana and cocaine do not check for steroids, which are potentially more destructive.
"For a small district to do this kind of testing would be cost-prohibitive," Joseph Wilimek, school superintendent in Angels Camp.
At Bret Harte High School in Angels Camp, all student athletes and cheerleaders undergo urine tests for marijuana, cocaine and other illegal drugs each season, costing the district about $9,000. Checking for steroids would cost an additional $44,000.
That would be enough money to pay for another teacher, Wilimek said. "Right now our priority is keeping staff — we've had to lay off three teachers and reduce our administrative staff already."
Steroids soared in popularity among high school students — girls as well as boys — after Mark McGwire hit a record 70 home runs in 1998 while using the supplement androstenedione, a steroid precursor.
In a recent national survey of steroid use, 3.5 percent of high school seniors responding reported they have used steroids at least once, up from 2.1 percent in 1991.
Those figures do not include users of over-the-counter supplements such asor the more popular creatine, which are much cheaper than steroids.
"There was a big increase when Mark McGwire broke the home run record. Of course he was using andro, but that may have been a distinction lost on a lot of the kids," said Lloyd Johnston, who led the University of Michigan survey of 50,000 teenagers. "If you're looking at a classroom of 30 boys, one of them is using steroids."
Johnston said steroid use is more prevalent among boys than girls, among whites than blacks and among non-college-bound students than those who plan to attend college. Many of the high school kids who use them are apparently non-athletes simply hoping to appear more buff.
Steroid use appears to be much higher in some parts of the country, particularly the South. In a 2001 survey by the Centers for Disease Control and Prevention, 11.2 percent of Louisiana high school boys surveyed reported using steroids and 5.7 percent of Tennessee high school girls acknowledged such use.
Steroids' side effects can include heart disease, liver damage and rage. They can also stunt growth, shrink testicles and cause girls to grow facial hair.
Many high schools use an NCAA-approved test for marijuana, cocaine, amphetamines and methamphetamine that costs about $22, plus collecting and handling expenses. But a steroid test costs $50 to $100, not counting collecting and handling.
Few school districts are willing to spend that kind of money.
In Florida, state Rep. Marcelo Llorente wants high school athletes to undergo mandatory testing for steroids. His bill, which would require each county to randomly test at least 5 percent of its athletes, was approved unanimously this week by a legislative subcommittee.
To reduce the cost, Llorente wants the tests to be done for about $33 each by the University of Florida veterinary laboratory that now tests samples from horses and greyhounds.
"I played three sports in high school and had the opportunity to play Division I baseball," Llorente said, who attended Tulane University. "I knew people who used performance-enhancing drugs. Young people don't understand the drastic consequences of using steroids."
In California, state Sen. Jackie Speier has introduced legislation to ban the sale of supplements such as andro to teens. She convened a Senate hearing Thursday to focus on the possibility of state-mandated testing and other ways to fight high school use of steroids and supplements.
"We teach kids not to take candy from strangers, but how many know not to take performance-enhancers from their friends and mentors?" she asked.
Among those testifying at the hearing was Kevin Will, 16, a junior quarterback at Del Oro High in Sacramento. He said coaches have warned the team not to use cocaine or marijuana, but he was never told not to use steroids.
And while he was never pressured by coaches to use steroids, he said, "I was told by friends and coaches I can play on the college level, but I have to get bigger." Will, who is 6 feet tall and weighs 168 pounds, said he has never taken steroids.
One of the few school systems checking for steroids is the relatively wealthy Paradise Valley district in Phoenix, where random tests have been conducted since 1992. The $50 tests are administered to student athletes involved in everything from football to cheerleading and badminton.
Students participating in sports must sign a drug-testing consent form. Positive test result in a suspension of 18 weeks from the sport for a first offense and a permanent suspension for a second offense. Results are not shared with law enforcement officials.
"The additional cost of testing for steroids is well worth it if we can protect our kids," said district spokeswoman Judi Willis. "We also believe the fact that we do this testing has been a deterrent."