Antibody to herpes simplex virus (HSV) type 1 and Epstein-Barr virus (EBV) capsid antibody were determined in 333 children from the Faroe Islands, aged 4, 8 and 13 years. An analysis of multi-way frequency tables was performed, testing seropositivity for each virus against combinations of the following variables: sibship size, birth order, mother's age at birth, birth weight, actual height and weight, age and sex. HSV-seropositivity was associated to sibship size, height and age, while EBV-seropositivity was related only to age.--It is discussed how the findings fit into epidemiological patterns described for Hodgkin's disease and multiple sclerosis, which are both supposed to be of viral origin. Our results suggest that HSV, but not EBV, may be among the candidates to be considered.