A new study from Northwestern University has found what it calls proof that bisexuality exists. While many people greeted this news with a deafening yawn, some bi-activists are feeling validated — after all, popular and scientific opinion often stereotypes bisexuals as reluctant, closeted homosexuals. Another point of view: That the research is so obvious it’s demeaning. "Someone who is bisexual might say, 'Well, duh!'" says investigator Allen Rosenthal, the lead author of the study. Here, a brief guide to the latest research:

How was this study conducted?
Scientists gathered a group of 100 men, divided into roughly equal numbers of straight, gay, or bisexual individuals. A "bisexual" was defined as someone who'd had sexual contact with at least two people of each sex and a relationship lasting three months or longer with at least one person of each sex. The 100 men were monitored for erectile arousal while they watched videos of male and female same-sex intimacy (a.k.a. gay and lesbian porn).

What were the results?
The study, published in the journal Biological Psychology, found that the men who identified themselves as gay or straight were aroused by either the gay video or the lesbian video, but only the bisexual men were aroused by both. These results confirm the findings of an earlier study from March 2011, published in the Archives of Sexual Behavior, that reported bisexuals were more likely to be aroused by videos showing different sexual couplings.

Did we really need a study to confirm that bisexuals exist?
Yes, according to some bi-activists. Older studies had advanced the view that people were either gay, straight, or lying. A widely publicized 2005 report, for instance, also from Northwestern University, found no hard evidence of bisexual arousal.

What’s the response from the bisexual community?
Mixed. "They’re proving what we in the community already know," says Jim Larsen of the Bisexual Organizing Project, as quoted in The New York Times. "It’s insulting." Others complain that the research dehumanizes human sexuality. "This unfortunately reduces sexuality and relationships to just sexual stimulation," says Ellyn Ruthstrom of the Bisexual Resource Center. "Researchers want to fit bi attraction into a little box. That’s nonsense."

Sources: LA Times, NY Times, PubMed, TIME