Boys tend to be more antisocial and aggressive if their fathers work extremely long hours -- 55 or more hours a week, researchers in Germany and Australia say. Jianghong Li, a senior researcher at the WZB Berlin Social Science Center, and four Australian co-authors said the longitudinal study was based on data of more than 1,400 children in Western Australia. About 19 percent of Western Australian fathers worked 55 or more hours per week when their children were age 5 and almost 20 percent of Australian fathers worked 55 or more hours per week when their children were age 8. The study, published in the Journal of Marriage and Family, found boys whose fathers worked 55 or more hours per week later exhibited more delinquent and aggressive behaviors than boys whose fathers worked fewer hours. However, the fathers\' long work hours did not appear to affect girls\' behaviors. Mothers\' work hours did not seem to matter, although few Australian mothers worked long hours and no firm conclusions could be drawn yet from this comparison, Li said. The culture of working long hours has crept into many jobs in the new economy. In Germany, 15 percent of fathers of children with similar ages of 3-4 worked 55 or more hours per week in 2011, the researchers said.