Certain reproductive biological disturbances have been demonstrated in case of human, mammalian and avian intoxications caused by pesticides. Organic (methyl-, dimethyl) mercury, passing through the placenta, disturbs the development of embryonic nervous system. Known teratogenic effect of dioxin has been confirmed by certain human examples that caused significant public health problems in Vietnam, Italy and New-Zealand. Reproductive biological problems in cattle originated from the oestrogenic effect of 2,4-D were reported by Hungarian authors in the 70s. The author has pointed out that chlorophenoxy-acetic acids increase the nitrite content of plants that helps to the formation of toxic nitrosamines which - after experimental embryonic exposition - can cause postnatal cerebral and renal tumors. As a result of the disposition for biomagnification in case of DDT, death of embryo in avian eggs can be expected. In other cases, it causes the disturbance of egg formation. Uptake of TMTD in the organism of birds may also cause egg formation disturbances which is accompanied by disadvantages of reproductive failures. Finally, the author has pointed out the possibilities of the prevention, safety tests to be carried out on experimental animals and monitoring that can promote the Good Agricultural Practice. It has been outlined that the licensing process is stringent in Hungary and harmonizes with the international requirements.
