I don't think that they have an actual devious trait, although I remember that in one of the commercial/preview they had for it. I think that that was from the old version before they edited it for...
I saw on a youtube video made by Sims 3 about killing your sims (Don't ask, I get rather bored) and they mentioned making your Sims fat and they can diabetes. However, I have zillions of fat Sims but...
You can have a total of 8 sims per household so when you have 8 sims a sims in your house cannot become pregnant and if you have the fertility treatment and you have 7 sims in your house and that sim...
You cant, at all in sims 3, but in sims 1 and 2 you can get a tattoo if you are playing on xbox, but they arnt custom tattoos with ambitions you can.go to cas and make a sim with them,go to the spa...