Working for the same employer as your partner hits hard on your home life, especially if you have no children. On the other hand, parents who work together appear to benefit from the arrangement.

Professor Phyllis Moen from Cornell University announced these findings at the American Association for the Advancement of Science (AAAS) annual expo.

She has studied hundreds of couples in large companies and universities.

"The number of co-working couples are increasing," she said. "And I wanted to find out if this made them better able to manage their lives."

"Most surprising to me were the results in childless co-working couples. Being a co-worker seems to have predominantly negative effects on co-working women and, to a lesser extent, men."

'Switching gear'

She found that childless co-working women were less successful at work than women who worked for a different employer to their partner. They also did much more housework and felt less secure about keeping their jobs, despite actually having held them for longer.

When they can't disengage by focusing on children at the end of the day, the stress of work tends to pervade non-worktime

Prof Phyllis Moen

Childless co-working men suffered too, having the highest levels of work-related stress and depression compared to co-working fathers or men who did not co-work.

Professor Moen thinks the reason for these effects relate to whether people "switch gear" when they come home from work.

"When they can't disengage by focusing on children at the end of the day, the stress of work tends to pervade non-worktime," she said.

This need to change focus if there are children to be looked after seems to lead to benefits for co-working parents. Professor Moen said they tended to co-operate more regarding housework and to value each other's careers more.