“It ends up robbing women of their potential,” Gates said in an interview. “This is a societal issue that in 2016 shouldn’t exist anymore.”

According to Gates, “globally, women spend an average of 4.5 hours a day on unpaid work. Men spend less than half that much time.” The unpaid labor gap is especially large in poor countries. “In India, to take one example, women spend about six hours, and men spend less than one hour,” she writes.

And when women are too busy cleaning and cooking, they have less time for paid work. Girls in many countries fall behind in school because they’re swamped with tedious chores. Gates writes that reducing women’s unpaid labor from five hours per day to three can increase a country’s female labor-force participation rate by 10 percent. If women participated in the economy at the same levels as men, she writes, global GDP could increase by 12 percent.