The New York Times, which based its report on an analysis of census results, said 51 percent of women in 2005 reported living without a spouse, up from 35 percent in 1950 and 49 percent in 2000.

"Coupled with the fact that in 2005 married couples became a minority of all American households for the first time, the trend could ultimately shape social and workplace policies, including the ways government and employers distribute benefits," the newspaper said.

It said that several factors are behind the shift including women marrying at a later age and living with partners for more often and for longer periods. Women are also living longer as widows and once divorced, often opt to stay single, the report said.

According to the Census figures, only about 30 percent of black women are living with a spouse, compared with 49 percent of Hispanic women, 55 percent of non-Hispanic white women and more than 60 percent of Asian women.