Polybrominated biphenyls (PBBs) and perchlorinated terphenyls (PCTs) are industrial chemicals that are long-lasting environmental contaminants. Although in vivo effects of PBBs on reproduction are documented, no information is available on the effects of these chemicals on sperm-egg interactions or fertilization. The present study was undertaken to determine the toxic potential of PBBs and PCTs on in vitro fertilization (IVF) in the mouse. 2-Bromobiphenyl, 4-bromobiphenyl, o-terphenyl, m-terphenyl, and p-terphenyl were added to the IVF medium at various concentrations. Oocytes collected from superovulated B6D2F1 mice were maintained in a medium containing the chemicals. Capacitated sperm were then added and the dishes cultured in a humidified atmosphere at 37 degrees C in 5% CO2 + 95% air. Oocytes were assessed for fertilization 20-24 h after insemination. polybrominated biphenyls and PCTs reduced the IVF rate at the higher dosages. Furthermore, an increased incidence of abnormal two-cell embryos and degenerative oocytes was observed at the 1 and 10 micrograms/ml concentrations of PBBs and PCTs. These results indicate that PBBs and PCTs adversely effect IVF and increase the incidence of abnormal embryos and oocyte degeneration in the mouse.