Girls have the potential to change the world. If we unlock this potential, the cycle of poverty in the developing world can be broken. But this will only be achieved if girls are freed from the threat of violence so many of them currently live under.
The scale of violence against children - especially girls - is enormous. Recent surveys from some countries in Africa show that about one in three girls has an unwanted sexual experience before the age of 18 and about one in four girls' first sexual experience is forced. Young women continue to have the largest percentage of new HIV infections in South Africa and one study estimates that 12 per cent of these infections could be prevented by addressing violence, especially sexual violence, against girls.
The long-term impact can be huge. Girls who experience violence are much more likely to drop out of school, have an unwanted pregnancy and - because pregnancy before the age of 18 is particularly high risk - they are more likely to die during childbirth.
CHANGING SOCIAL NORMS
There are two ways to address violence: prevention and response. Recently, development programmes have tended to focus on response because they've been built on top of health services to provide access to anti-retrovirals, for example to prevent HIV. Making sure victims have access to the services and treatment they need is essential, but we need to do more to prevent violence too.
Prevention is much tougher because it involves changing deeply engrained social norms - in particular the idea that violence is normal and acceptable, or that girls and women deserve violence because they have done something wrong. A husband beating his wife because she burns the dinner, a girl blaming herself for being raped - these things should not be considered normal, but too often they are.
These attitudes permeate whole communities and hold everyone back, creating an unspoken culture of fear that impacts a girl's participation in society at large. Many girls drop out of school, often for safety reasons, leaving themselves isolated and unable to play a role in the social and economic development of their community.
TACKLING THE ROOT CAUSES
Addressing these social norms and the gender power structures that reinforce them is difficult - but not impossible.
At Together For Girls - a partnership between five UN agencies (including Unicef and UNAids), the US government and the private sector - we work with governments and local organisations in the developing world to collect qualitative and quantitative data about violence against girls so that governments and communities can tackle these difficult issues in an informed and evidence-based manner.
This data is used by governments to launch national action plans that tackle the root causes of violence, as well as to strengthen systems to better protect both girls and boys. For example, in Tanzania - one of the five countries, including Swaziland, Kenya, Zimbabwe and Haiti, that we have completed surveys in - they are now establishing district-level child protection teams that bring together social services, health, education, police and the courts to protect children identified as vulnerable.
There are more surveys in the pipeline in Cambodia, Indonesia, Malawi, Nigeria and the Philippines. It's important to stress that these countries came to us to create a partnership, not the other way round: they recognise there's a problem and they tell us they want support in tackling it.
That's why the governments of the five countries we've already worked with have really seized on the data to mobilise robust action against violence. One of the most stunning examples is in Swaziland, where they drafted two bills in response to the survey results: the Child Welfare Bill, which was signed into law in September 2012, and the Sexual Offences and Domestic Violence Bill, which has just passed through both legislative Houses.
These laws will ensure there are chid protection teams to assist schools, health services and the police to get to the root causes of violence - as well as respond to it.
Crucially, these laws are designed to enable the government to work with the police and justice systems to make sure that the perpetrators of violence can no longer act with impunity. In many countries the justice system is not in a position to properly enforce the laws against violence - a situation that reinforces social norms and the culture of fear.
By using data from our surveys to form a better understanding of the causes, context and consequences of violence, Swaziland is starting to overcome that problem.
But it doesn't stop there. The development community must do much more to ensure that girls are not held back by the fear of violence within their communities.
Girls themselves have power and are a vital part of the solution. Interventions such as economic empowerment programmes and safe-space programmes empower girls with the connections, role models and assets they need in order to have greater control over their lives, which in turn reinforces the idea that violence against girls is not acceptable.
For example, in Tanzania we are working to help empower more girls by accessing media training and safe spaces with our new Catapult and Chime for Change project with Unicef.
We know that all these solutions work. Now we need to scale them so that developing countries are making strides at both a national and community level to prevent violence against girls.