For the 574 million teenage girls in the world today, what must the future look like?They’re growing up in the midst of the greatest refugee crisis in our history, Zika virus and its threats to reproductive health, and gender inequities that continue to hold many back from education, health care, and income. Each day, we face the threats of terrorism. Of a warming planet. Of political instability. Of constant attacks on the vulnerable—many of whom are young women and girls.Despite all of this, we at IntraHealth International can’t help but be optimistic.

We see the challenges girls face every day in countries around the world. Many of the hardships they endure come to the surface when they step into a health care setting, whether it’s a doctor’s office or a community health worker’s hut.

Health workers have the power to change girls’ lives.

But we also know that health workers have the power to change girls’ lives—whether it’s by offering contraceptives without judgement, delivering the results of an HIV test with compassion, or asking a girl about violence in her home or relationships.Health workers who are well trained and deployed as part of strong, functioning health systems are uniquely positioned to educate, empower, and inspire the young people they care for. They know how to build trust. And they can educate entire communities about the potential of young women, often keeping them from being married too young, providing them with the future planning tools they need, and protecting their health and human rights.And positive interactions with health workers make young people more likely to consider becoming health workers themselves someday.

That’s why we work with health workers and health systems around the world to invest in young people, particularly girls. And it’s why we’re so excited for what the future could hold for us all.

In honor of World Population Day 2016, we’re looking back at 16 stories from the past year that could shape the future of our population—whether it’s one country or one girl at a time.

1. On World Population Day, Let's Do More for the World
2. Have an Unmet (Contraceptive) Need?
3. Out with 'Family' Planning, In with 'Future' Planning
4. Youth Advocates Can Increase the Use of Modern Contraceptives, If We Listen to Them
5. Video: End Shame: Restore Dignity for Women with Fistula Today
6. In Tanzania, 22.8% of Teen Girls Are Mothers
7. Once an At-Risk Youth, Thembi Becomes a Child & Youth Care Worker
8. New Contraceptive Gives Women More of What They Want
9. Kenya’s Nurses Can Empower Women through Family Planning
10. What Will Family Planning Look Like in 2036?
11. When She’s Not Ready to Have Another Baby Yet
12. Social Service Workers Can Help End Violence against Women
13. 16 Ways Health Workers Can Help Stop Gender-Based Violence
14. Future Planning: Young People Making Choices
15. What's the Recipe for Family Planning Progress in Senegal?
16. Move Over, Unmet Need—There’s a New Family Planning Indicator in Town