I understand that things like that are not part of someone's personality, it's a part of life... so I agree that putting things like that next to bookworm and lazy feels a bit wrong...but that's how the game works so I understand why they made lactose intolerant a trait.
I think if the sims team wanted to add more controversial things from real life I would prefer that they were not hidden. The game have a lot of hidden traits that we have no control over and I would prefer to have the choice to include things like that in the game... then you could choose yourself to make it genetic or not. When I age a kid up I often pick one trait from the parents so their traits are sort of genetic.
