The U.N. population agency is urging greater investment in 10-year-old girls saying that what happens at that age can determine their futures.

The State of World Population 2016 launched Thursday says more than half the world's 60 million 10-year-old girls live in countries considered to have the worst gender equality and are less likely than boys to finish school and more likely to be forced to work and to be child brides.

The U.N. Population Fund said if all 10-year-old girls in developing countries who never attend school or drop out early were to complete secondary education, their earnings would trigger a $21 billion annual dividend.

Ten is a pivotal age for girls as puberty approaches because of choices that start being made about education, work, marriage and child bearing.