If you have a family tree, avoid 6 generations, and if you don’t have a family tree, avoid 4 generations. That’s your great-grandfather, your grandfather. Your son should avoid words used in your father's name, as well as the names of your wife, your mother, your grandmother, and your wife. Your children should avoid the name of your great-grandfather’s father, and your children should avoid the name of your great-grandfather’s grandfather.