Until recently in the developed world, most married couples adopted traditional roles, with the husband working outside the home and the wife taking care of the children and the house. Although many families still follow this1 , those roles have become less2 . A number of factors have contributed to this change.3 , perhaps as a consequence of feminism （女权运动）, people have begun to4 that one's5 should not determine one's role. As a6 , people feel they have "7 " to decide what they want to do in life. It's no longer8 for men to want to be the primary caregiver or homemaker. Similarly, many women would9 to enter the working world instead of staying at home. Moreover, a large number of women have10 advanced academic professional training,11 them with a significant earning potential.
On the other hand, factors other than personal choice have12 to the fluidity （不稳定性） of gender roles. Life has become more expensive and it's13 for a family to exist on only one income, requiring married women to leave the home to14 money to help support the family.15 , the number of two-income households has16 rapidly. And despite the fact that women on average still earn17 than men for the same job, their incomes have become an18 component of survival and prosperity in today's world. In similar fashion, a man's decision to19 at home may not be voluntary. In the event he has lost his job, his decision to stay at home might be one of20 , not choice.
