The first group was made up of 112 fathers who helped in the home more than the average Dutchman. The researchers found the division of tasks was important for the father's physical well-being; it deteriorated significantly if he had to do more work than the mother. The second study group comprised 140 fathers aged between 37 and 56.
One theory for the negative effect on men's health is that women act as family "directors of health", taking responsibility for the household's healthy eating, physical exercise, drinking habits, bedtimes, medication and so on. This role is diminished if she works a lot and is often away from home.
Even as young girls, the Dutch sociologists argue, women learn to pay special attention to the mental and physical health of themselves and others, whereas boys are more likely to engage in risky, sometimes unhealthy, behaviour. When they start a family, therefore, women tend to assume responsibility for the health of their husbands and children, as well as themselves.
A second explanation - the "unfulfilled husband" theory - focuses on the psychologically symbolic impact of having a wife who works. Men can feel inadequate if their wives work or earn more than they do; they lose power and status and regard themselves as failures as breadwinners.
So which explanation is the most plausible? The data partly confirms both, but the unfulfilled husband hypothesis seems the stronger. The authors of the study, published in Patient Education and Counselling, argue that the two hypotheses have a common element: upbringing. In the first, girls learn that they have to take care of their own and others' health; in the second, boys learn that work, a career, and earning money are the most important things in life. Much government policy promotes women's participation in the labour market, but future policy, the researchers argue, should focus on persuading men to take more responsibility for their own and others'
Dr Raj Persaud is Gresham professor for public understanding of psychiatry, and director of the Centre for Public Engagement, King's College London.
His latest book is The Motivated Mind (Bantam Press). Email: firstname.lastname@example.org