Washington State University researchers have established a categorical distinction between people who are heterosexual and those who are not. By analyzing the reported sexual behavior, identity and attraction of more than 33,000 American adults, they found that 3 percent of men and 2.7 percent of women are not heterosexual. They also found notable issues on several mental health fronts.

The findings are a clear departure from the homosexual-heterosexual continuum used to describe sexual orientation since it was hypothesized by sexologist Alfred Kinsey in 1948. However, the findings do support more recent biological hypotheses of sexual orientation.
“There are distinct qualitative differences in sexual orientation, which means that there are distinct categories of people based on sexual orientation,” said Alyssa Norris, a WSU doctoral candidate and lead author of the study, published in the journal Psychological Science.

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