<prompt> Radiation exposure during infancy has been linked toBreastMelanomaThyroidLung  <response>: Ans. c ThyroidRef: Robbins pathology 9th ed. 109 The most radio-sensitive organ sites in children in the order of sensitivity are thyroid, breasts, bone marrow and brain. Exposure to ionizing radiation in first 2 decades predisposes a person for development of papillary CA. 