nraas

Is there a way to use master controller to make an elder sim the grandparent of a young adult sim? 

Yes, but not directly. In TS3 there must be a sim in between on the family tree (the parent). MC Cheats can be used to specify the child of the elder and then the child of the parent. Or the other way around by specifying the parent of the child then the parent of the parent. The parent in between doesn't have to be alive necessarily, but they do have to exist within the game.

It's the same with uncles/aunts and nephews/nieces. There has to be a sibling in between to have the kids in order for the uncle/aunt relationship to exist.

NRaas > MC > (Sim) > Advanced > Family > Add (Parent, Sibling, Child)

Hey igazor,

Since there is a way to edit a family relationship, is there a way to completely UNDO a family relationship? I'm just curious....I actually was looking earlier today but couldn't either find it or wasn't understanding if there was a way or not.

Thanks in advance,

Cheers
Bowlady

There should be an option to Remove Parent or Child depending on the sim you click, same route as Add Parent/Child.