Q: What is the role of a stepparent in parenting teenage step-children? My 19-year-old stepson moved in with us several months ago and is disrupting our marriage. He does what he wants when he wants, and there are no consequences. How does one deal with a child that age when he refuses to follow the rules of the house?

A: Contrary to the advice given by most mental-health professionals, even Dr. Phil, the proper role of a stepparent is to be a responsible parent, with all the privileges and authority pertaining thereto. The operative word is the noun “parent,” not the prefix, “step.” The same applies to the word “stepfamily.”

The problem in many, if not most, of today’s so-called stepfamilies is that the stepparent effectively is disempowered by the “real” parent; therefore, the children do not have reason to respect or obey the stepparent. In these families, the emphasis is on the prefix “step.” I think it is significant that you didn’t mention your husband, but certainly implied that he enables his son’s disrespect of you and disregard of rules by imposing no consequences on his provocative, narcissistic behavior.

It is your husband’s responsibility to straighten out this young man, to let him know that he does not have permission to treat his wife with anything but the utmost respect. Is your husband willing to do that? Is he willing to put his foot down and tell his son that it’s either his way or the highway? If he’s not, then I am not going to pull any punches here: He’s lost his spine. But if so, he is in the company of many equally spineless men who value their relationships with the children of their first marriages over their relationships with their current spouses.

And by the way, this indictment is not limited to male parents. There are plenty of mothers out there who will not let their stephusbands discipline children who are not “their own.”

In my estimation, a 19-year-old who disrespects a stepparent and will not follow the rules of the house should find his own house — tomorrow, if not sooner. While he is away, change the locks, put his possessions on the front stoop and pin a note to them wishing him well in his new adventure.

A psychologist, Rosemond answers parents’ questions at www.rosemond.com.