Forty percent of employed Americans work late hours or weekends or both, which can cause family life to suffer. Harriet Presser, a sociologist at the University of Maryland, found that parents working nights are more likely to separate or divorce than those on other work schedules. Childcare and health concerns such as sleep deprivation also pose challenges to workers with non-standard hours.
See "More working parents play 'beat the clock'", Marilyn Gardner, The Christian Science Monitor, June 1, 2004