A new survey reports that 75% of Americans didn't receive any information about gay sex in their sex ed classes.

Bespoke Surgical surveyed more than 1,000 adult Americans ages 18 to 55 about the sexual education they received growing up. The results illustrate longstanding problems with American sex ed: LGBT issues and relationships are often omitted from curriculums altogether.

"What our survey found—and confirmed by the LGBT community—is that the school systems in America are failing LGBT youth, both currently and historically," researcher David Cusick tells NewNowNext. "Sex ed in the United States is far from comprehensive. So many LGBT individuals have to turn to other outlets, like YouTube, bloggers, and friends for their education. These alternative sources generally lacking validity, accuracy, and overall merit."

Cusick's team at Go Fish Digital analyzed the results, breaking them down by gender, geographic location, and sexual identity: Interestingly, heterosexual participants were most likely to report learning about queer sex, while gays and bisexuals were less so. Potentially, straight respondents felt any cursory mention of homosexuality was sufficient.

"To have such a stark difference in responses indicates that there may be more than meets the eye," Bespoke said in a statement.

Respondents were also asked about their main source of sex education: Some 26% of straights and 21% of gays reported they learned the Birds and the Bees at school, while a fifth of bisexuals said the Internet was their main teacher.

Bi participants were also much less likely to get their sexual education from friends—and much more likely to receive sex ed from "trial and error."

Currently, only 12 states mandate discussion of LGBT topics in sex ed, compared to the 37 states that require teaching abstinence. (Of those, 26 require that abstinence be "stressed.")

"School systems should teach their students about the complexities of gender and sexuality," says Bespoke CEO Evan Goldstein. "By bringing these issues to light, we hope we can help make the much needed changes to the curriculum, allowing students the advantages of a proper education they need and deserve."