Fathers in two-income families need to "step up" even more, a new study says, to help mothers who are frequently multitasking when it comes to chores, childcare and work and who are feeling the stress of it.

Working fathers aren't exactly slouches when it comes to multitasking; they spend 39 hours per week doing at least two tasks at once. But working mothers spend 48 hours per week multitasking, according to the study, and they are more likely to do the grunt work of household chores and childcare.

"Fathers, by contrast, tend to engage in other types of activities when they multitask at home, such as talking to a third person or engaging in self-care. These are less burdensome experiences," said Shira Offer, one of two authors of the study, which was released Thursday and published in the American Sociological Review.

(I don't precisely know what self-care means, but I have been known to help my kids with their homework while brushing my teeth. So maybe that's it.)

Performing two work-related tasks at once is the most common form of multitasking -- constituting 36 percent of the weekly multitasking for fathers and 23 percent for mothers, the study found. But mothers are much more likely to perform childcare and chores at the same time (10 percent for mothers versus 4 percent for fathers) and to perform two household chores at once. Fathers are more likely than mothers to perform work and transportation tasks at the same time -- perhaps talking to clients while driving to or from the office.

It was no surprise to the authors, then, that mothers feel more stressed by multitasking than men. Part of this is due to the nagging social expectations that women must be the homemakers. Women are more likely to feel guilty about multitasking instead of focusing on their kids, and judged when multitasking in public settings, the authors concluded.

"Although (fathers) are also expected to be involved in their children's lives and do household chores, fathers are still considered to be the family's major provider," Offer said. "As a result, fathers face less normative pressures and are under less scrutiny when they perform and multitask at home and in public."

The research was based on existing data from the 500 Family Study, which examined middle-class families in eight U.S. cities and their daily activities from 1999 to 2000. Most of the families in the study were highly-educated and working in professional occupations.

Does this study reflect your experience? And do you think the results would be different today? The data is more than a decade old, after all, and collected at a time when the supposed timesavers of iPads and smart phones didn't exist.

And on the lighter side of the issue, enjoy this picture: