The governments of many of the poorest countries in the world are crying out for financial support for family planning, but are not getting it. The lives of countless millions of women are devastated by their inability to manage their own fertility, and hundreds of thousands die every year because of illegal abortions or complications from unwanted pregnancies. But their voices go largely unheard. On top of all that, every single one of the environmental problems we face today is exacerbated by population growth, and the already massive challenge of achieving an 80% cut in greenhouse gases by 2050 is rendered completely fantastical by the prospective arrival of another 2.5 billion people over the next 40 years.
Being food secure, energy secure, and water secure...is very much harder the higher human population is and the faster it grows. Sex and relationships education the world over has never been more important.