Some environmental factors and hypotheses for stuttering in families with several stutterers

Individuals in families with several stutterers (five or more) and individuals in families with no stutterers were the basis of a broad study designed to elucidate both genetic and nongenetic factors relevant to stuttering. In order to examine both nongenetic hypotheses regarding the etiology of stuttering as well as environmental factors possibly predisposing to stuttering, data were collected using two structured case-history interviews and four self-report inventories. We were unable to identify prenatal, developmental, or medical factors that distinguish stutterers from their nonstuttering family members. Further, we found no evidence of (a) anxiety levels differing among stutterers, their nonstuttering family members, and nonstuttering controls; (b) familial attitudes toward speech differing between nonstuttering family members and those of nonstuttering controls; or (c) ratings of parental behavior or children's traits which distinguished stutterers from nonstuttering family members.