The government introduced this requirement in the 1980s after studies showed major inconsistencies in how judges were awarding support, both within and among states. For the family in the study, formulas that look only at the father's earnings produce high totals. As the number of working mothers has ballooned in recent decades, most states have moved to formulas that factor in both parents' incomes. Historically, many states calculated child support by taking a percentage of money earned by the...