AbstractEighteen children born to parents who had previously received chemotherapy or radiotherapy were examined for physical health, growth, and development. The immunologic and the hematologic status of these children was also evaluated. Their ages ranged from birth to 15 years. The children had a careful history and physical examination to detect any abnormal symptoms or signs, and the parent's previous treatment was carefully documented. Four sets of parents had children while one of the parents was on active treatment (2 male and 2 female). Of the male patients, one patient's wife had a baby that was“small for gestational age”at birth and had transient failure to thrive; the other child was normal. Of the female patients, one offspring was small for gestational age at birth and the other was normal, but both continued to have failure to thrive for up to 17 months and 26 months, respectively. Ten parents procreated after being treated with chemotherapy and/or radiotherapy, to whom 14 children were born. One child was a stillbirth with multiple congenital abnormalities, and another child had trisomy 13–15 and died 6 months later. The other 12 children were normal at birth, but one child is under the 5th percentile for growth at twelve months of age. In all children studied, immune function test, complete blood count, and viral tilers were considered normal for age. In our study, we found that three out of four children born to parents who were on chemotherapy had failure to thrive. Of the 14 children born to parents who conceived after being off chemotherapy, 11 were found to be normal in growth and development. These results imply that there is a high risk of complications in children born to parents who procreated while receiving chemotherapy. Further studies are needed to develop better guidelines for counseling cancer patients who want to have children.