"Irreversible changes" have gradually been forged in men's minds that has made them recognize their obligation to help their wives out with household chores and child care, according to an Israeli-American study on changing family roles. The new research, co-authored by Ben-Gurion University of the Negev sociology and anthropology Prof. Oriel Sullivan and University of California at Riverside Prof. Scott Coltrane, reveals that the switch has occurred not only among younger men but also among older ones who were raised in homes where their mothers did almost all of the work at home. The study also showed that the longer a wife works, the more housework her husband does. The two researchers, affiliated with the Council on Contemporary Families, note that over the last 30 years, marital equality is increasing and more couples are sharing family tasks than ever before, especially among full-time, dual-earner couples. "Most previous literature on the division of family work began with the naive assumption that the massive gender rearrangements that began in the late 1960s would, unlike any other major social transformation in history, have instantaneous results," said Sullivan. "Our ongoing studies of couple relationships reveal instead that change has been continuous and significant, not merely in younger couples who begin their relationship with more flexible ideas about gender, but also in older couples where the wife has worked long enough to change her husband's values and behaviors. Men and women may not be fully equal yet, but the rules of the game have been profoundly and irreversibly changed." In the US, men's absolute and proportionate contributions to household tasks increased substantially over the past three decades, dramatically lessening the burden on women. Studies show that from the 1960s to the 21st century, men's contribution to housework doubled, increasing from about 15 to more than 30 percent of the total. The most dramatic increase in men's contributions has been to child care. Between 1965 and 2003, men tripled the amount of time they spent in child care. Fathers in two-parent households now spend more time with children who live with them than at any time since large-scale longitudinally comparable data were collected. The researchers said these trends were occurring in much of the Western industrial world, including Israel, suggesting a worldwide movement toward men and women sharing the responsibilities of both work-life and family life. Data from 20 industrialized countries over the period 1965 to 2003 reveal an overall cross-country increase in men's proportional contribution to family work (including housework, child care and shopping), from less than one-fifth in 1965 to more than a third by 2003. There is, overall, a striking convergence of work-family patterns for men and women. While the total hours of work (including both paid and family work) done by men and women have remained roughly equal since the 1960s, there has been a growing convergence in the hours that both women and men spend in the broad categories of paid work, family work and leisure. Women's paid work time has significantly increased, while that of men has decreased. Correspondingly, women's time devoted to housework has decreased, while the time men spend in family work of all kinds has increased.