“…The maternal effect on development has been studied in rats (Naso et al, 1975;Leamy, 1977;Atchley and Rutledge, 1980;Kasser et al, 1983aKasser et al, ,b, 1986a, mice (Wahlsten, 19831, and humans (Hoshi, 1973;Nakata et al, 1974;Chung et al, 1986;Malhotra et al, 1987). The maternal effect comprises both genetic and nongenetic factors, which are collectively referred to as "congenital variation" in the present study.…”