“not easily acceptable as meaningful in terms of cause and effect” (Yerushalmy, 1962). An interview survey of 982 pregnancies indicated a strong dose-response association between paternal cigarette smoking and the percent of infants weighing less than 5 pounds, 8 ounces (Yerushalmy, 1962). In a later prospective study of nearly 13,000 births, Yerushalmy (1971) reported that paternal smoking was more strongly associated with low birthweight than was maternal smoking. The healthiest low-birthweight infants were found for couples where the wife smoked and her husband did not; the highest mortality rate was found among infants produced by couples where the husband smoked and the wife did not. These latter couples also had increased risks of producing premature offspring. The possibility that these differences in smoking were associated with differences in social class was not explored. On the bases of these data, Yerushalmy (1971) inferred that paternal smoking may be incidental to birthweight. When the mother’s smoking was considered, the importance of paternal smoking disappeared.
In a study of 12,192 births, MacMahon et al. (1966) confirmed the negative association between maternal smoking and birthweight of offspring and also found that infants of fathers who smoked weighed about 3 ounces less than those of fathers who did not smoke. They attributed this finding to the correlation between husbands’ and wives’ smoking habits, or to chance. MacMahon et al. (1966) referred to Yerushalmy’s (1962) observation of an association of father’s smoking habits with infant weight as “biologically nonsensical.”
In a study of 175 normal neonates and 202 neonates with congenital malformations, Borlee et al. (1978) found that paternal smoking was independently and significantly associated with reduced birthweight and higher perinatal mortality. They speculated that the effect occurred through its association with another factor. Gibel and Blumberg (1973) reported on a study of 5,000 children in which children of nonsmoking mothers whose fathers smoked more than 10 cigarettes per day had higher perinatal mortality than children whose parents were both nonsmokers. The incidence of severe malformations in children of fathers who were heavy smokers was double that of children of nonsmoking fathers, independent of parental age and social class.