With the Klingons, it'd be a bit problematic, considering that any attempt to initiate a mating ritual would be interpreted as an attack by another male Klingon—unless, of course, it was delivered with a bit of that far-famed Klingon love poetry. Perhaps that's the only time it's acceptable to flee from battle, eh? "Huhr?!" Other than the Dax/Khan kiss (which could be dismissed as residual affection derived from a heterosexual relationship), we have little overt evidence of homosexual behavior in Star Trek, which could mean any number of things, in universe, such as: It's entirely a non-issue and completely acceptable under IDIC, but not particularly widespread It was a uniquely human genetic aberration that died out as man began to tinker with his genome—subtly (or not-so-subtly) discouraged so as to aid children in avoiding a still-prevalent stigma; in addition, I certainly think gays might have been targeted during the Eugenics Wars, and those of Colonel Green It proved correctible with advanced medical and/or psychological techniques I'm not espousing any of the above, by the way. Each of them, though, is a logical outgrowth of a particular perspective on the origins of/motivations for homosexuality. I do think various undercurrents of homoeroticism were subtly woven into the Trek tapestry, though: The Seven of Nine/Janeway, Reed/Hayes and Garak/Bashir relationships seemed to possess certain elements that could be interpreted as sexual interplay or tension—though that's certainly not the only way to interpret various of these interactions.