San Francisco has become the first city in the United States to require that its companies provide their employees with paid parental leave. A new law, approved by the city's Board of Supervisors to come into force in 2017, mandates that firms over a certain size (with 50 employees at first, dropping to 20 in 2018) give new mothers and fathers six weeks of paid time off. Californian law already guaranteed that 55 percent of wages would be provided by a state disability program, but San Francisco's new rules mean that the remaining 45 percent will be provided by employers, up to a salary ceiling of $106,740 per year.

The move comes as many of the city's biggest tech companies are stepping up their own parental leave programs. Twitter announced this week that it would now offer 20 weeks of fully paid leave for any employee with a new baby, copying policies put in place by Facebook and Etsy, among others. Other states, too, are pushing through new legislation that gives new parents more time off. From 2021, private-sector workers in New York will get 12 weeks of paid family leave, as per a new bill signed by the state's governor on Monday, expanding on rules that already give the roughly 20,000 people employed by New York City six weeks of paid leave.