It’s hard enough to persuade sexually active people to remember to use birth control consistently—harder still when they suspect that doing so might cause them harm. According to a new survey, a belief persists in the African-American community that the government and medical authorities do not tell the truth about the safety and reliability of contraception methods.

From slavery through the notorious Tuskegee experiments in the mid-20th century—when blacks were used as uninformed subjects in syphillis research—African Americans have had cause to mistrust information presented by the authorities. Many apparently still do. A survey published in the latest issue of Health Education and Behavior questioned 500 African-Americans between the ages of 15 and 44, and found that one third believe medical researchers use blacks as guinea pigs for unproven forms of contraception. About 25%  believe that “poor and minority women are sometimes forced to be sterilized by the government,” and 22% believe that government policies are designed “to control the number of black people.”

That’s not a prescription for good contraception use. Women who believed in contraception but also believed the conspiracy theories were found to be less likely to use any birth-control method prescribed by a doctor, such as pills or implantable devices; men who believe the theories were likelier to resist birth control overall. Despite that, 78% of the people polled who had had at least one sexual partner of the opposite gender did say they use some contraception method, but how consistently is uncertain. That still leaves a significant percentage of people entirely unprotected, vulnerable to unwanted pregnancies and sexually transmitted diseases.

Researchers believe their findings highlight the need for greater education on sexual health and contraception, particularly from people and organizations other than white-coated doctors, in order to put to rest the stubborn rumors.