Which brings me to another question... Your thoughts on characters having off-screen sex? Do they act differently afterward? Do the other characters pick up on it? Have you been in campaigns in which you could sense a change in other characters? Could you tell if other characters were acting differently, could you sense the chemistry between them?
Have you ever wanted to get two other characters together? I've encountered this before, in which other players wanted two characters to get together. If the group needs to split up, those characters are paired. Other players will often force those characters to room together, or influence scenarios in which those two characters are alone together.
Again, robots with no sex.
Holosuite girls can't sex either (to my knowledge) so Josei's gonna be sex free, FOREVER.
As for pairing with other characters, I wouldn't do anything like that without the express consent of the other person. And even then I probably wouldn't even do that as I'm far too uncomfortable asking people to do something with their character.