Imagine a world where everyone – all 8 billion of us – has a future bursting with promise and potential. Now open your eyes to the current reality that 4 billion women and girls – half of humanity – face discrimination solely based on their gender.

Thirty years ago, at the International Conference on Population and Development (ICPD), we set out to achieve a world in which people lived longer, healthier lives and enjoyed more rights and choices than ever before. This vision has become a reality for many; in fact, the human population is at its highest number ever, thanks in large part to improvements in health care and increased longevity. Yet, as we celebrate the progress that has been made, we must also recognize that for millions, even billions, of others this promise remains out of reach.

This World Population Day is a reminder that we can achieve the prosperous, peaceful and sustainable future envisioned by the ICPD and the 2030 Agenda for Sustainable Development if we harness the power of every human being on the planet. When we unlock the full potential of women and girls – encouraging and nurturing their desires for their lives, their families and their careers – we galvanize half the leadership, ideas, innovation, and creativity to better society.

Realizing sexual and reproductive health and rights for all is the foundation for gender equality, dignity and opportunity. Nevertheless, over 40 per cent of women around the world cannot exercise their right to make decisions as fundamental as whether or not to have children. Empowering women and girls, including through education and access to modern contraception, helps to support them in their aspirations — and to chart the path of their own lives.

Advancing gender equality is a crosscutting solution to many population concerns. In ageing societies that worry about labour productivity, achieving gender parity in the workforce is the most effective way to improve output and income growth. Meanwhile, in countries experiencing rapid population growth, women’s empowerment through education and family planning can bring enormous benefits by way of human capital and inclusive economic growth.

Thirty years ago, the world united behind a shared vision of the future, one that recognized the rights of women and girls as central to global development. The solution is clear: Accelerating the advancement of gender equality – through access to sexual and reproductive health and rights, improved education, appropriate labour policies, and equitable norms in the workplace and home – will result in healthier families, stronger economies, and resilient societies.

That message of gender equality is as powerful today as it was then; our resolve must be as well. Let us unite once more to imagine a world in which every one of us has the equal opportunity to thrive, and let us join forces to ensure a reality in which every nation’s real wealth – no matter its size or stage of development – is its people, and that means all people, not half.

UNFPA stands with all 8 billion people so that they may claim their rights and make their own choices. Because only that will lead to a future that will bring equality and prosperity to us all.