The names and addresses of these families were obtained from New York State birth records for Erie County. These birth records were pre-selected to exclude families with premature (gestational age of 35 weeks or lower), or low birth weight infants (birth weight of less than 2500 g), maternal age of less than 19 or greater than 40 at the time of the infant's birth, plural births (e.g., twins), and infants with congenital anomalies, palsies, or drug withdrawal symptoms. Introductory letters were sent to a large number of families (n=9457) who met these basic eligibility criteria. Each letter included a form that all families were asked to complete and return. Approximately 25% of these families completed the form and of these, 2285 replies (96%) indicated an interest in the study. Respondents were compared to the overall population with respect to information collected on the birth records. These analyses indicated a slight tendency for infants of responders to have higher Apgar1 scores (M=8.97 vs. 8.94 on a scale ranging from 1 to 10), higher birth weight (M=3516 vs. 3460 g), and a
