What would happen if, at the stroke of midnight tonight, every woman in Europe lost access to contraceptives? How many girls would drop out of school? How many women would quit their jobs? Could parents provide for their children? What new phrase would we have to coin to express the catastrophe that would befall economies that are already in “crisis”? More than 200m women and girls in poor countries, mostly in Africa and south Asia, do not have access to contraceptives. That is more than all the women of reproductive age in Europe. I have made family planning my priority, because the women I meet when I travel consistently tell me that having the power to decide when to have a child is central to achieving their goals in life. They want to be able to feed their children, take them to the doctor when they are ill, and send them to school so they can fulfil their potential. This week, our foundation is joining the UK’s Department for International Development in sponsoring the London Summit on Family Planning, which brings together thousands of partners around a single ambition: to provide 120m additional women with access to contraceptives by 2020. The summit builds on a long history of success in extending access to contraceptives to poor women. Family planning programmes have been around for more than 50 years, and they have helped transform most of Asia, Latin America and the Middle East. But progress has slowed in recent years. Among many donors, especially in Europe, the idea of access to contraceptives is so uncontroversial that it hardly seems worth investing in. Conversely, in countries such as the US, the issue has become a proxy for the fight over abortion, so it is too controversial to invest in. Meanwhile, hundreds of millions of women are unable to make basic decisions about their future. Our objective is to remind everyone that there should be no controversy – but a strong sense of urgency – around giving women the power to make a better life for themselves and their children. Over the years, we have learnt countless lessons about how to do this work better. There are three big themes running through the summit. First, and most important, we are putting women and girls at the centre. In the past, some programmes put too much emphasis on trying to manage population growth. Some of these set specific population targets, and some even resorted to coercion to reach them. Participants in the summit agree that empowering women and girls to make their own decisions is the best and only way to encourage large-scale economic and social improvements. Second, the work is being led by stakeholders in the countries where it is happening. More than 20 countries have been reviewing data and pinpointing weaknesses in their family planning programmes. They are announcing plans to address these gaps at the summit. None of the investments we are discussing is being imposed; we are relying on the commitment and expertise of those in the countries where women who do not have access live. Third, there is a diverse group working more collaboratively to break through the barriers blocking progress. In particular, the private sector is playing a much bigger role. In Senegal, for example, our foundation is working on a pilot project that provides incentives to small businesses to make sure contraceptives are always in stock at the health clinics, which has been a serious problem. Drug companies are working with countries to supply high-quality products at affordable prices. UN agencies are working with countries to streamline the regulatory approval processes, so that more companies can enter the market. Companies are also working with universities and non-profit groups on research and development to create products that meet more of women’s needs. For example, injectable contraceptives that could be administered by women in their homes would be more practical for women who live far away from health clinics.. What if 120m women such as these had access to contraceptives by 2020? How many more girls could go to school? How many more women could work? How many more parents could provide for their children? What new phrase would we have to coin for the economic progress in some of the poorest parts of the world?