Eighty-three children born to heroin-dependent mothers were compared with 76 children born to heroin-dependent fathers and to three control groups: 50 children with environmental deprivation, 50 normal children from families of moderate or high socioeconomic class without environmental deprivation, and 80 healthy children from kindergartens in Jerusalem. The children were examined at 6 months through 6 years of age by a developmental pediatrician and a developmental psychologist using the Bayley Developmental Scales for children up to 2.5 years of age and the McCarthy Scales for Children's Abilities for children ages 3-6. Results revealed that 6 percent of the children born to heroin-dependent mothers and 7.9 percent of those born to heroin-dependent fathers had significant neurological damage. The children born to heroin-dependent mothers had a lower birth weight and a lower head circumference than controls. The children of heroin- dependent parents also had a higher incidence of hyperactivity, inattention, and behavioral problems. Children born to heroin-dependent mothers who were adopted functioned similarly to the controls, while those not adopted functioned significantly lower than others. Findings indicated that the developmental delay and behavioral disorders among children born to drug-dependent parents raised at home may result mainly form severe environmental deprivation and the addiction of one or both parents. The specific role of prenatal heroin exposure seems to be less important than home environment. Tables and 45 references (Author abstract modified)