New York, Feb 6 (IANS): As blended families become more common, stepfathers with multiple parenting roles are at higher risk of depression, says a study.

Depression risk increases for both men and women when the number of parenting roles they hold increases and some stepfathers experience the highest stress levels, the findings showed.

Parents in a "yours, mine and ours" family hold three parenting roles: one each for the two families that blended, and a third when a child is born into the blended family.

According to the study, parents with three roles were 57 percent more likely to be depressed than those with just a single parenting role.

"If you say parenting and depression, the first thing people think of is post-partum moms," said Kevin Shafer, a professor of social work at Brigham Young University in the US.

"But both moms and dads experience stress and certain kinds of parenting roles can be very, very stressful," Shafer noted.

The risk is even higher for fathers in such blended families when a father has biological children who do not live with him.

"There are norms that govern parenting, but there are not norms for being a step parent," Shafer pointed out.

The risk is driven partially by feelings of guilt for spending more time with his new children than his older children. The dynamic also shifts when a new baby comes along, Shafer added.

The study was published in the journal Social Work.