Divorce researcher Judith Wallerstein dies

In 1970, preschool teachers asked California psychologist Judith Wallerstein how to deal with a rash of children who couldn't sleep, cried constantly or were aggressive with playmates. The common denominator, the teachers said, was that the parents were divorcing.

Wallerstein looked for research on the issue and, finding nothing useful, decided to conduct her own. She launched what would become a 25-year investigation, producing alarming findings that made the long-married grandmother of five a polarizing figure in a contentious national debate.

Once described by Time magazine as the "godmother of the backlash against divorce," Wallerstein died June 18 in Piedmont, Calif., after surgery for an intestinal blockage, her daughter Amy Wallerstein Friedman said. She was 90.

When Wallerstein began looking at the impact of divorce, she thought the children's difficulties would be fleeting. Instead, she found that for half of the 131 children she studied, time did not heal their wounds but allowed them to fester, creating "worried, underachieving, self-deprecating young men and women" who struggled with romantic relationships.

"What in many instances may be the best thing for the parents may by no means be the best thing for the children," she told Newsday in 1994. "It is a real moral problem."