Among married couples who had first lived together for three years or more, the divorce rate was 50 percent higher, they found.

The average number of births among white married couples is estimated to have dropped by nearly half between 1800 and 1900.

Now, however, it is mostly among university students and young couples who cannot afford the high cost of marriage.

"Among younger professional couples," he said, "we are seeing an increase in the size and quality of stone."

Among married couples with two or more children, 73 percent of those earning less than $100,000 would be hit.

There were only four pregnancies among couples in the study during the test period.

Not many dates qualify, however, which makes for some significant competition among couples.

Some who weren't single acted as if they were, and a few arguments broke out among couples.

The disparity was even more pronounced among black married couples.