More than half the world's women and girls experience some kind of physical or sexual violence in their early years.
This miserable tide of suffering is ruining millions of girls' childhoods and undermining their chances of becoming healthy adults.
There may be nothing more corrosive to our societies than allowing this assault to continue.
Yet there are some signs of hope. Girls are standing up for themselves, or with their peers, and calling for an end to the violence. A growing movement is coalescing around ending this injustice. Societies are starting to realise that an evil they may have taken for granted doesn't have to last forever.
A meeting takes place today [Wednesday 20 September] in New York which could significantly improve the condition of girls and women around the world.
The European Union will demonstrate global leadership by announcing half a billion Euros of investment in United Nations efforts to promote women's empowerment and ending violence against women and girls.
We will be attending as enthusiastic partners - and with a strong message that the world's leaders must get the foundation right if this welcome infusion of cash is to have a real, long-term benefit.
And what is that foundation? Tackling violence against girls is primary, not an afterthought.
We won't succeed in equipping women to be safe, protected and empowered if we don't begin by protecting them as children. Of course, we know that the way boys are treated in early childhood is a big predictor of how they will treat women and girls later in life.
The abuse of women is atrocious. There is nothing more disempowering for a woman than to have endured a childhood of violence, rape, or forced labour, or to have lost that childhood entirely by being married while still a child.
Every civilised country needs laws to protect girls, but those laws also need to be enforced. A law, without arrests and successful prosecution, is meaningless.
We must each challenge our own cultural traditions which harm girls, from genital mutilation to early marriage, from enforced labour to physical punishment.
Children, families, schools and communities should show their girls respect and cherish them - and show them how to raise the alarm when their rights are infringed.
This will need investment, but good examples spread quickly.
For example, in the "Grand Nord" of eastern Democratic Republic of the Congo, where violence against girls is almost routine, a teenager called Esperance decided enough was enough. She formed a group she called One Girl One Leader, in Beni town, and in the years since then attracted dozens of teens and young people in their 20s, who speak out to local authorities, traditional leaders and religious groups about protecting girls.
16-year-old Akter in Khulna, Bangladesh, formed a similar activist group to save her peers from early marriage and other forms of sexual abuse. Akter has since had the opportunity to travel the world to encourage her peers to take their own stand.
Heartening stories like this are widespread, but need to become much more common. We all have a stake in enabling our girls to speak up for themselves, to survive, develop and thrive.
To promote the protection of girls and boys, UNICEF and others in the UN family, together with civil society and private foundations, initiated the Global Partnership to End Violence Against Children, a hub bringing partners together to build political will, strengthen collaboration and accelerate action. World Vision has committed itself to a five year campaign, It Takes A World, as its response to a global epidemic that is spread - or stopped - by the daily choices of everyone on the planet.
Removing the threat of violence in childhood years gives young women a chance to be healthy, educated and safe in a way that can hardly be achieved later in their life. It gives them the opportunity to get decent jobs, earn for their living and to take advantage of any targeted initiatives and measures aimed to foster greater economic empowerment of women.
The fifth Sustainable Development Goal is the world's promise to achieve gender equity and end violence against women and girls. We can only make progress on that if we are honest about the distinctive vulnerabilities of girls.
This is a rare window of hope, when we see the possibility of genuine change in favour of the world's girls. The European Union promise is not just the provision of cash, it is an injection of hope. Properly focused and used to generate still more support, it could change the future for millions of the next generation of women and girls.