Betting on dice on the streets of Baltimore or wagering on favorite sports teams may seem innocuous behavior for city teenagers, but it can serve as a gateway to heavier gambling and other risky behavior, impairing lives for years to come.

These are the findings of researchers at the Johns Hopkins University who repeatedly surveyed a group of up to 798 disadvantaged teenagers beginning in 2004. The latest results culled from the surveys linked gambling among the youth to early sex, sometimes resulting in pregnancies and sexually transmitted diseases.

The findings come as Baltimore is poised to welcome a Las Vegas-style casino this year, providing more enticement for young people in some of the city's toughest neighborhoods to start a habit that some may find addicting. They also come as operators strive to keep youths out of the casinos and as the General Assembly passed legislation to establish fines for underage gamblers caught on gaming floors.

Advertising alone for the new casinos could spur the more impulsive types to sneak into the facilities or gamble closer to home and engage in other risky behaviors such as sex, drugs and alcohol, the researchers found.

"Just because you live in a disadvantaged Baltimore neighborhood, you're not more likely to be impulsive," said Dr. Silvia Martins, who led the research at Johns Hopkins' Bloomberg School of Public Health and has published a nearly a dozen papers on Baltimore youths and gambling. "But there would likely be less prevention strategies in place to control those who are impulsive."

The newest study, now online at the journal Addictive Behaviors, found that almost half of 427 youths had gambled before age 18 and more of the gamblers had initiated sex in that time. About a third of the gamblers had intercourse by age 13 and almost 90 percent had by age 18. Nine percent of the sexually active youth had contracted a sexually transmitted disease.

Of those who had gambled, close to half were frequent gamblers.

Other studies in the series, led by Martins, now an associate professor of epidemiology at Columbia University's Mailman School of Public Health, found that gambling could lead to depression, crime, homelessness and joblessness in young adulthood.

The researchers said these kids may have more chaos and violence in their lives, a deeper attraction to quick riches and better access to the lottery and other gambling opportunities such as card and dice games. They also may have little to stop them.

The research concluded that youth in disadvantaged communities are 12 times as likely as those in more stable areas to have gambling problems.

Martins said gambling needs to be added to existing programs aimed at heading off teenage drug use and other risky behaviors. More treatment options also are needed.

Grace Lee, who worked on the research as a graduate student at Johns Hopkins, said more parental monitoring helps deflect gambling troubles, but it can't stop all risky behavior.

"It's not that parents aren't watching in these neighborhoods," said Lee, now an analyst at the National Institutes of Health. "It would be even worse if they weren't. But it's the environment."

There are efforts underway to make teens, as well as teachers and counselors, aware of the potential for gambling problems in the city.

Those involved at the casinos already work to limit underage gambling there. So far, few youths have been caught on the Maryland gaming floors — about three dozen, who jumped walls from restaurants, used fake IDs or otherwise initially evaded security, according to state data reported by casinos.

The casinos have been fined 10 times for a total of $46,000 for underage infractions, according to the Maryland Lottery and Gaming Control Agency, which oversees casinos.

For now, the only repercussion for those who sneak into a casino is getting ejected, said Stephen Martino, the agency director.

But the agency and casino operators supported legislation passed by the General Assembly allowing those under age 21 to be fined $100 for the first infraction, $500 for the second and $1,000 for the third, which also would include referral to gambling counselors for evaluation, said Martino, who is also chair of the Maryland Alliance for Responsible Gambling, formed by gambling, state and health interests to pursue policy initiatives.

Martino said he believes there aren't too many more underage youth getting past security or video surveillance. At Maryland Live in Anne Arundel County, the largest of the casinos, officials have begun using electronic identification readers.

"It's really been a point of emphasis," Martino said. "But there needs to be accountability on both sides. Right now, the burden is on the casino."