They found that about 15 percent of the sample overall disagreed that bisexuality was a real sexual orientation. Straight men were three times more likely than any other group to disbelieve in bisexuality. Women, white people and people who identified as gay, lesbian or bisexual showed the least amount of anti-bisexual bias. However, the researchers cautioned, gays and lesbians were more negative about bisexuality than bisexuals themselves, suggesting that prejudice against bisexuality still exists in the gay community. Male bisexuals were viewed more negatively than female bisexuals. (Women are more likely than men to identify as bisexual.)

Stigma can make it hard for bisexual people to feel socially connected, Friedman said in a statement.

“Having hard data to back up why a bisexual person might feel the need to be secretive about sexual orientation, something that can lead to higher depression and many other negative health outcomes, is very useful to people trying to fight stigma and marginalization,” he said. “For example, this information can guide social marketing interventions and outreach to reduce that stigma, and improve rates of HIV prevention, testing and treatment within the bisexual community.”