This week marks the 20th anniversary of the Rio Earth Summit, the pivotal 1992 event that put climate change on the international map. The theme of this year’s Rio+20 summit is sustainable development — economic growth that sustains us in the present without placing the lives and welfare of future generations in jeopardy.

Many of the most daunting and important challenges of the 21st century are the subjects of debate and negotiation at the Summit: How we create and use energy, confront global climate change, and adjust to a rapidly growing population.

Yes, these are huge challenges, but in the last 20 years we have learned one clear and resounding truth: that a commitment to protect the rights of women and young people around the world is a critical step toward a sustainable future.

There are 200 million women in the world who want to use contraception to prevent pregnancy, but don’t have access to these basic services. Access to integrated reproductive health services for all is essential — including maternity care and safe, effective, affordable and acceptable modern methods of contraception. By reducing maternal and child mortality and improving the health of women, these health services have a powerful impact on sustainable development.

Access to modern birth control isn’t a side issue — we truly can’t have sustainable development without it. Empowering women creates a positive ripple effect — creating healthy and more prosperous families and communities, slowing population growth, and helping restore the balance between people and the air, land and water we all depend upon for life.

In so doing, we will also dramatically slow the growth of dangerous greenhouse gas emissions — to the same degree as if we increased the world’s reliance on wind power dramatically, scaled up the efficiency of buildings and vehicles, or made huge strides in reducing deforestation. Now that’s a huge win for women, families and for the planet.

We are also too far behind in ensuring access to comprehensive sexuality education. An essential, powerful impact of the Rio+20 negotiations would be to affirm the human rights of women, men and adolescents to make decisions related to their sexuality, including sexual and reproductive health, free from coercion, discrimination and violence.

But isn’t that too controversial to make progress on now? No, because despite the recent dustups in the United States, public opinion polls consistently show that the vast majority of Americans believe family planning is essential and support open access to contraception here and abroad.

Rio+20 presents a once-in-a-generation opportunity to ensure that women’s health, reproductive rights, and sexuality education are recognized and incorporated in our vision of and an action plan for our shared sustainable future. This is the moment to transform the human side of sustainable development into reality.