Sex changes and pesticides

The Danish Environmental Protection Agency has published research arguing that aspects of male reproductive health have changed dramatically for the worse over the past 30-50 years, and that exposure to oestrogenic chemicals may be a cause(1, 2).
    The Danish work suggests that environmental factors such as the exposure of the male foetus to higher levels of oestrogen may be having an adverse effect on the reproductive capacity and well-being of diverse species. Although research showing that man-made chemicals could be oestrogenic when administered to test animals dates from 1938, the issue has now surfaced because of the increasing incidence in human and wildlife populations of the adverse effects predicted, and because of the increasing numbers of environmental oestrogens to which we are being exposed.
    Results show male sperm counts may have decreased by 2% per annum over the past two decades. For some men, fertility may be impaired. Testicular cancer is now the most common form of cancer in young men. Hypospadias is also increasing in incidence.
    Results suggest that reproductive impairment follows exposure of a number of species-including, fish, birds and mammals-to oestrogenic chemicals in the environment (see PN23)(3). Candidate chemicals include some organochlorines, such as DDT, and tributyltin pesticides.
    The report presents a detailed summary of research in the field, including methods for evaluation of oestrogenic effects and human exposure, and suggests a research strategy to investigate the ideas further. It also contains a useful appendix of toxicological summaries of the principal pesticides and other chemicals implicated.

1. Danish Ministry of Environment, Male Reproductive Health and Environmental Chemicals with Oestrogenic Effects, Copenhagen, DKK 185, Denmark 1995, 166 pp.
2. Editorial: Male reproductive health and environmental oestrogens, The Lancet, 1995, 345:933-35.
3. Link, A. and Buffin, D., Endocrine Disruptors Pesticides News 23, 1994.

[This article first appeared in Pesticides News No. 28, June 1995, page 26]