If only 10-20 percent of the population are Narcissists is it possible that an entire family of 7 could all be Narcissists?

Answer 1

It's Plausible.It's entirely possible, because personality traits and coping mechanisms are at least dramatically influenced by, if not established by, the developmental environment.While many parents prefer to think that their children's issues were something that they were born with, of whole cloth, in reality the coping mechanisms taught by the parents and other role models, through example and otherwise, are a key guide for the personality of the adult who arises from the process.

So a family with two parents who are narcissistic could, easily, produce a batch of children who are, and whose children will be. This is not a foregone conclusion, because some specific personalities don't create the right environment to pass themselves on, and can even produce a child of the opposite traits...but it's still possible, even plausible.