Introduction

At the beginning of the 21st century, we are in a unique but precarious position. Economic globalisation, accelerating technological change, expanding industrialisation and shifting political and religious forces have provided great opportunities and challenges. Equally important, a growing number of scientific studies and reviews suggest that our reproductive health and, ultimately, our reproductive capacity are under strain. These studies report increases in reproductive diseases and decline in reproductive function since the mid-20th century among certain locations and populations. Examples are shown in figure 1 from readily available data primarily from developed countries.1–4

Genetic changes cannot explain the decline in reproductive health and function and external factors are likely to play a role, with environmental chemicals identified as one suspect risk factor.3 5 6 Over roughly the same period, manufacture and use of both natural and synthetic chemicals has increased by over 20-fold,7 with approximately 87 000 chemical substances registered for use in United States commerce as of 2006, and about 3000 chemicals manufactured or imported in excess of 1 million pounds each.8 These chemicals contaminate our air, water and food supply; we are also exposed through the use of a wide range of consumer and personal care products. Data from the National Health and Nutrition Examination Survey show that everyone in the USA has measurable levels of multiple environmental contaminants in his/her body. These findings have been mirrored in studies in Europe and it is expected that exposures are ubiquitous worldwide.9 10

The power of environmental chemicals to impact reproductive health has been dramatically demonstrated through tragic episodes of food contamination and workplace exposure, including severe neurological, reproductive and developmental effects caused by mercury and polychlorinated biphenyl (PCB) poisonings in Japan and Taiwan, and male …