Sustainable development depends on maintaining long-term economic, social, and environmental capital. In failing to make the best use of their female populations, most countries are underinvesting in the human capital needed to assure sustainabilitly. This market and systems failure is discussed in this publication in terms of gender constraints, which are based on the socially-constructed and historically developed roles of men and women. It also illuminates how female contributions can be better realized at present and how strategies can be developed for meeting the needs of future generations. This report is a contribution by the OECD to the UN Commission on Sustainable Development and its cross-cutting work on gender.