Equal property splits in divorces make men richer and women substantially poorer, a California study has found, buttressing nationwide efforts to include a husband's potential earnings in settlements.

The study of 3,000 divorces by a Stanford University researcher shows men improved their standard of living an average 42 percent in the first year after a divorce while the living standard for women and children dropped 73 percent when income was compared to need.

The finding has considerable economic significance at a time when more than 40 percent of U.S. marriages begun in the 1980s are expected to end in divorce and only 56 percent of American children by the 1990s are expected to grow up with both natural parents.

California appeals court judges are now considering the case of Sullivan vs. Sullivan, in which a divorced wife is seeking additional money from her ex-husband, a physician, to compensate for her help in putting him through medical school.

According to University of California at Davis law professor Carol Bruch, courts in several other states are also being asked to include the value of a husband's education in divorce property settlements.

Lenore J. Weitzman, a senior research associate in the Stanford sociology department who prepared the California study, wrote in a UCLA Law Review article that younger divorced women should receive larger payments to finance training for their own careers.

"Although the husband has fewer dollars than before divorce," Weitzman said, "he is not constrained to share those dollars with his former wife and children. Thus the demands on his income have diminished. . . . Many divorced men have received salary increases over the year after their divorce , while their obligations for alimony and child support have remained fixed or diminished."

While the appeals court ponders the Sullivan case, the state government is considering changes in the law to soften the blow to women and children from divorce. Bruch, who also serves as a consultant to the California Law Revision Commission, said the resources of men and women after divorce "are so disparate they knock your socks off."

Bruch said the problem appears to be particularly acute in California because state law forces judges to split property 50-50. That usually forces a couple to sell their house in order to make an equal division. "It means that mothers are going to be stuck in rental housing with the kids, and it really has an effect on kids," Bruch said.

In many other states, judges have more discretion in dividing property, Bruch said, but courts outside California are also considering giving women more benefits if they have sacrificed their careers to establish their husbands in business or a profession.

In a 1980 New Jersey case, she said, a doctor's wife was awarded 20 percent of what the court determined to be the value of his medical education, to be paid in installments that increased as his earnings increased.

Weitzman's study includes a random survey of 500 divorce decrees from San Francisco and Los Angeles counties for each of three years--1968, 1972 and 1977. The project also includes interviews with 44 family law judges and 169 divorce attorneys in the two counties and with 114 recently divorced men and 114 recently divorced women in the Los Angeles area.

Weitzman said that even after 10 or 15 years of marriage, most of the couples had less than $20,000 in combined net assets, giving a wife without a career half of a small pie. In California, Weitzman said, only one in six women receive alimony. Child support payments, when paid at all, typically do not cover half the costs of child rearing.

"For many couples who have little physical property to divide at divorce, it is likely that the monetary value of career assets will considerably exceed the value of their physical property," Weitzman said.

"I would argue that we are on the brink of a critical expansion of the traditional definition of community property. California courts will soon recognize career assets as part of the community property to be divided on divorce."

Men may help themselves by paying for further education of their ex-wives, Weitzman argued.

An Ohio State study shows women who go to school rather than get jobs after divorce eventually earn higher income and thus do not need to call on their ex-husbands' resources as much.