From Alex's post, "Why Hasn't Star Trek Ever Had a Queer Character?," Jon Trouten writes:
Star Trek was definitely always more about gender identity as opposed to sexual orientation. The J'naii characters in that one TNG episode (which really never made sense to me, but that's just me).
DS9 always seemed the most willing to address sexuality issues. There was the Mirror Universe Kira, who was clearly bisexual. Also, there was Dax, who had lived different lifetimes as both men and women. One specific storyline introduced Jadzia Dax to one of her former spouses. Both hosts were female and they were briefly intimate with each other before breaking up again.
Several readers left comments about a Star Trek episode that never made it to air, but let's expand the topic a week bit. What sci-fi show do you think was the most LGBT-friendly?