SAN FRANCISCO — San Francisco approved a measure Tuesday making it the first place in the nation to require businesses to provide fully paid leave for new parents.

Advocates say the issue is gaining momentum across the country much like the debate over a higher minimum wage.

The San Francisco Board of Supervisors voted unanimously in favor of the measure after supporters said six weeks of fully paid leave is needed because too many families can’t afford to take time off after a child is born or adopted.

Small business owners countered that it’s the latest in a long list of city mandates – including paid sick leave and health coverage – that unfairly targets them.

Federal law grants workers up to 12 weeks of unpaid leave. California, Rhode Island and New Jersey provide partial pay, with the money coming from employees. Legislators in New York last month approved up to 12 weeks of partial pay.

The state of California currently allows workers to receive 55 percent of their pay for up to six weeks to bond with a new child. The money comes from a state insurance program funded by workers.

The San Francisco measure requires employers with at least 20 employees to make up the rest.

Businesses with at least 50 employees must comply starting in January 2017. Businesses with at least 20 employees have until January 2018 to comply.