Trek hasn't explored very many of the character's sex lives? What?
Kirk seemed to be on a one man mission to spread the human genome throughout the galaxy...(het)
Scotty had a couple of love affairs, both in Lights of Zetar, and Wolf in the Fold...(het)
Uhura was pretty attracted to that crewman in Man Trap... and even helped Kirk seal the first interracial kiss on TV.. (het)
Spock was up for hanky panky with T'pring, a Romulan Commander, Mariette Hartley in bearskins, ready to buy the farm and settle down in another episode...(het)
Checkov was ready to do some tom foolery with some of Harry Mudd's female androids, and a fake cowgirl in a hallucination about the OK corral, etc. etc... (het)
Bones McCoy was going to marry a high Priestess, and, as Dax noted, "Had hands of a surgeon..." (het)
There were also indications that Sulu was the ladies man with a foil... (Naked Time)
Chapel was carrying a torch for Spock (het)
Hell, even Lt. Leslie, seen in the background of most of the episodes, was give a scene where he was "checking out" one of Mudds Women in sickbay... (het)
Remember, this whole Kirk and Spock thing is an invention of the slash writing fandom, and none of it is considered cannon by anyone with any connection to the Trek franchise. None of it. Not one bit. So the slash porn in interesting, BUT it is not to be taken seriously...
In the meantime, on other series, we have Capt. Jack Harkness, Chianna on Farscape, Anara on Firefly, and several of the Cylon models on BSG... All of whom seem to be perfectly accepted, and contributin members of their crews/teams.
Number Two: Conform, Number Six! Conform!
Number Six: I will not be stamped, filed, indexed, briefed, debriefed, or numbered! I am a person.