How Do You Deal With A Disrespectful Step Child?

I had a mom comment on how much she loves my "trouble questions" and had a problem that she needs some help with.

She has older step kids that are disrespectful. They talk back and verbally say mean hurtful things to her.

I don't have step kids, but do have kids of my own. Two of them are teenagers who have gotten a little lippy with me, but nothing mean or hurtful. More along the lines of disrespectful. All I have to do is remind them who the parent is and that if they talk to me like that again they will have things taken away that they love - car, cell phone, computer and gaming systems.

This works for me, but these are my own kids. I can't imagine having a child that may not be yours biologically, but that you help raise say awful things to you.

How do you deal with a disrespectful step child?