Identifying environmental factors harmful to reproduction.

Reproduction is essential for the continuation of the species and for life itself. In biological terms, living and reproducing are essentially one and the same. There is, therefore, no sharp division between identifying factors harmful to reproduction and identifying factors harmful to life or vice versa. Detection of harmful factors requires balanced use of a variety of methodologies from databases on structure-activity relationships through in vitro and in vivo test systems of varying complexity to surveys of wildlife and human populations. Human surveys provide the only assured means of discriminating between real and imagined harmful factors, but they are time consuming and provide information after the harm has been done. Test systems with whole animals provide the best prospects for identifying harmful factors quickly, but currently available methods used for testing agrochemicals and drugs need a thorough overhaul before they can provide a role model. Whether there is a need for new methodology is doubtful. More certain is the need to use existing methodology more wisely. We need a better understanding of the environment--whatever it is--and a more thoughtful approach to investigation of multifactorial situations.