The findings and methodological issues of epidemiologic studies on adverse developmental effects of parental occupational exposure to organic solvents are reviewed. The studies on maternal effects suggest that high exposure to solvents may increase the risk of spontaneous abortion, but the findings on congenital malformations are inconsistent. Suggestive associations of spontaneous abortions have also been observed with some particular solvents. The evidence appears to be most adequate for toluene. Evidence on the effects of paternal exposure to solvents on pregnancy outcome is limited and inconsistent. Suggestive results link paternal exposure to spontaneous abortion, congenital malformation, and low birth weight or preterm birth. A common methodological weakness in these studies is the inaccurate data on exposure. Positive findings encourage further studies with an improved study design and methods, particularly with improved assessment of exposure.