I think that since ghosts don't age, they won't let us age them up either. What Lena told me to do is age them up in cas using cheats. When they are aging up to adult, you have to use cheats to add their character value traits. If your dad is a vampire, he may get abducted, impregnated, and have a hybrid alien/vampire. They are not supported by the game and are very buggy. If you have that situation, you also have to use cheats to remove the vampire trait from them. You should be able to find all the cheats you need to use with a google search. Good luck!
If anything is wrong with what I said, I apologize. This is just what I was told to do in these circumstances, so I thought I could help out.