Analysts at Brown University found that the two groups of couples most likely to have a second child are those in which the man does much of the housework or in which the woman does most of the housework.

They found that 81 percent of couples in which the husband does at least half of the housework will have a second child. For couples in which the wife does most or all of the housework, the figure is 74 percent.

However, when the wife and the husband more or less share the domestic chores they are less likely to have a second child.

The research is summarized in the latest issue of Population Development and Review.

Researchers studied 265 dual-earner married couples who had at least one biological child under 16. Their information was collected within the larger National Survey of Families and Households first in 1987-88, and then again in 1992-94.