Only one-third of those who got married in the mid-1970s are still happy with their spouses, indicating a downward trend in marital happiness, a researcher said.

"The outlook for the institution of marriage is bleak," Norval Glenn, a University of Texas sociologist, said Thursday.Glenn's study of marital happiness, to be published in the National Journal of Sociology in March, concluded that only one-third of couples married in the mid-1970s are still together and happy with their marriages.

Similar studies done in the 1970s showed that 50 percent of people married in the 1960s were still together and happy, indicating that more couples are breaking up.

Glenn's study also found that women are more unhappy than men and that blacks are less happy than whites.

"It says something very negative about marriage," he said, adding that many marriages do not work these days because married people, especially women, are trying to do too much as full-time workers and parents."