From our Department of the Obvious - A University of Michigan study has shown that a husband creates an additional seven hours of housework for women, while wives save men an hour of housework per week.
The latest results of an ongoing study of housework trends showed a continued decline in hours of housework done by U.S. women since 1976, down from 26 hours to 17. The time men spend on housework, in contrast, has doubled, from six hours per week to 13.
Surprisingly, the study found that marriage increases the time spent on housework for both women and men. It also showed that single women in their 20s and 30s only spend an average of 12 hours a week on housework, while those in their 60s and 70s devote 21 hours a week.
More kids means more housework, as you might expect. Three kids raises a woman's housework to 28 per week. Surprisingly, men with more than three kids actually do far less housework on average, down to 10 hours per week. I'd speculate that the desire for a large family and the identification of housework as 'woman's work' are somehow related.
Gracias to Science Daily