A stepmother is a woman who is married but not related by blood or adoption to a child's parent. For example, the wife of a divorced man, who has remarried, is the stepmother of the children from his first marriage or any other unions.
Stepmothers can serve as disciplinarians for their stepchildren; however, this is usually most effective if the children are very young, explain Dr. Phil. The longer a stepmother plays a pivotal role in the lives of her stepchildren, the more likely she is to be taken seriously when she enforces rules in the home. It is also wise for stepmothers to be sources of support for their stepchildren and to provide guidance as needed, without trying to replace the children's biological mother.