What Doctors Don't Tell YouPrenatal exposure to polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) alters the structure and mobility of sperm and, thus, may affect the reproductive function of the exposed offspring, say Chinese researchers.
This conclusion was arrived at after studying the children of Taiwanese mothers who were poisonedin 1979 by the large scale ingestion of cooking oil contaminated with PCBs and PCDFs. In that year, over 2000 Taiwanese ingested a batch of contaminated rice oil. Soon after, the children of women who ingested the oil presented with a number of problems, including intrauterine growth retardation, skin and nail abnormalities, and poor neurocognitive development.
To determine whether the pesticides had any reproductive effects among young men who had been exposed prenatally, the researchers studied sperm samples taken from exposed teenagers and compared these with the sperm of non exposed boys of the same age.
The sperm of the exposed teenagers showed more structural abnormalities, reduced mobility and a reduced ability to penetrate hamster oocytes (egg cells). The researchers also found that, on average, the exposed youths were 2.7 cm shorter than the controls (Lancet, 2000; 356: 1240-1).
Reproductive effects due to pesticide exposure have also been found in Austria. Researchers studied the children of men accidentally exposed to high levels of dioxin in 1971.
The exposed men showed a tendency to produce more girls compared with unexposed men. While the trend was not considered significant, it does confirm the findings of other studies that dioxins can produce long term cellular reproductive effects, the extent of which we are only just beginning to understand (Lancet, 2000; 356: 1271-2).
Maryon Stewart
Tom Ferguson MD
Daniel Redwood DC