Popular movies may be sending unhealthy messages about sex and drug use.

A new study shows the vast majority of sex scenes in international blockbusters released in the last 20 years made no mention of any type birth control and none depicted the consequences of unprotected sex.

"The study showed there were no references to important consequences of unsafe sex such as HIV transmission, spread of STDs, or unwanted pregnancy," says researcher Hasantha Gunasekera of the Institute for Child Health Research at Children’s Hospital Westmead, Australia, in a news release. "The social norm being presented in movies is concerning given the HIV and illicit drug pandemics in developing and industrialized countries.”

In addition, researchers found that although drug use was portrayed less frequently than sex, it tended to be depicted in a positive light.

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Unsafe Sex at the Movies

In the study, researchers reviewed sexual activity, sexually transmitted disease prevention, birth control measures, alcohol and drug use, and any consequences of such depicted or discussed in the top 200 movies of all time based on box office receipts.

Of those top 200 movies, researchers excluded films released or set before the emergence of AIDS (pre-1983), animated movies, those not about humans, and those with G or PG ratings.

Of the remaining 87 movies that were reviewed, there were 53 sex episodes. In those sex scenes, researchers found:

—Only one suggestion of condom use, which was the only reference found to any form of birth control.

—Ninety-eight percent of sexual encounters that could have resulted in pregnancy did not include the use of birth control, nor was use of birth control suggested.

—None of the movies containing sex scenes depicted the consequences of unprotected sex, such as unintended pregnancies, HIV, or other sexually transmitted diseases.

The results appear in the Journal of the Royal Society of Medicine.

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Movies Show Drugs in Positive Light

The study also showed that marijuana and other noninjected illicit drugs were portrayed in movies less often than alcohol intoxication (32 percent) and tobacco (68 percent). But when illicit drugs were depicted, it was often in a positive light.

For example, of the 8 percent of movies depicting marijuana use, 52 percent showed it in a positive light and 48 percent showed it in a neutral light with no negative consequences.

Overall, the study showed that only one in four of the movies was free of unhealthy health practices, such as unprotected sex between new partners, marijuana use, noninjected illicit drug use, smoking, and alcohol intoxication.

"With globalization and the growth of home-based media technologies, movies are more accessible to a wider audience, and there is convincing evidence that the entertainment media influences behavior," says Gunasekera. "The motion picture industry should be encouraged to depict safer sex practices and the real consequences of unprotected sex and illicit drug use."

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By Jennifer Warner, reviewed by Louise Chang, MD

SOURCES: Gunasekera, H. Journal of the Royal Society of Medicine, October 2005; vol 98; pp 464-470. News release, Royal Society of Medicine.