“…For example, a number of epidemiologic studies have identified possible associations of parental occupational exposures with birth defects (Cordier et al, 1997;Correa-Villaseñ or et al, 1991Garcia et al, 1998;Khattak et al, 1999;Matte et al, 1993;McMartin et al, 1998;Olshan et al, 1991;Schnitzer et al, 1995;Shaw et al, 1999a,b;Tikkanen and Heinonen, 1992). However, because assessment of parental occupational exposures in these studies was based either on reported industry and job title, which lack information on specific exposures, or on self-reports of exposures to specific agents, which suffer from low sensitivity and potential recall bias (Garcia, 1998;Bauer et al, 1999), it is likely that the exposure groups evaluated included some misclassified subjects and that the observed odds ratios were biased and imprecise.…”