the reasons can be found in the workplace and at home.
On the one hand, more women have full-time jobs than 30 years ago.
On the other hand, the traditional role of the wife has not changed.
Women are still expected to raise the children and look after the hose.
They often don't get much help from their husbands.
Many woman manage the house in addition to doing a full-time job. One survey found that working women spend two hours each day on housework, while men spend about ten minutes.
Young working women may choose not to take on these extra responsibilities.
Sumi Kitade appears to support this view.
"I don't want to quit my job to become someone's slave," says Dr. Kitade