The rumored relationship between film star Zhang Ziyi and popular TV anchor Sa Beining has become a hot topic, and many netizens have expressed "concern" over it because the annual income of Zhang is about 790 million yuan ($127 million), almost 77 times that of Sa.

Irrespective of whether Zhang and Sa have fallen in love, the netizens' "concern" reflects the traditional Chinese thinking that men should earn more than their wives (or partners).

But in developed countries a growing number of women contribute more to family income than men. This trend is changing women's traditional role of being "helpless housewives" and challenging the perceived image of men as the "breadwinners".

Liza Mundy, author of The Richer Sex, wrote in the March 2012 cover story of Time that in the United States, nearly 4 out of every 10 working women earned more than their partners in 2009, an increase of more than 50 percent from 20 years ago.

While it's hard to estimate how many Chinese women earn more than their partners, they indeed are contributing an increasing share of household income. In the 1950s, women in China contributed 20 percent of household income, and the figure rose to about 40 percent by the 1990s, and 50 percent in 2009, according to BBC. Generally speaking, women in China still have fewer job opportunities, promotion chances and paid less than men, but that doesn't necessarily mean men should earn more than their wives.

According to a survey conducted by the women's federation and the National Bureau of Statistics in 2010, among people with higher education the number of women was 7.1 percent more then men. Gary S. Becker, the economics Nobel Prize winner, has said women's income may surpass that of men if the percentage of women opting for higher education continues.

In China, however, the traditional social pattern of marriage prevails. People still expect women to marry men who are older, taller and richer. But when some women begin to outperform their husbands or partners in income, people shouldn't use their traditional beliefs to judge their relationship.