NEW YORK, Aug 14 (Praxis Press) Advancing maternal age has been linked to a child's subsequent risk of type 1 diabetes, but most studies have not used genetically related siblings. Bingley and colleagues studied the interactive effects of parental age and birth order on childhood development of type 1 diabetes in a cohort of 1,375 families with at least one diabetic child. The risk of diabetes in offspring increased by 25% and 9% for each 5-year increment in maternal and paternal age, respectively. Women aged 45 years or older had a relative risk of 3.11 when compared with women under 20 years of age. Firstborn children had the greatest risk of developing type 1 diabetes, and the risk decreased by 15% for each additional child. Prenatal factors appear to play a role in the risk of type 1 diabetes in offspring, and postponement of childbearing may partly explain the increasing incidence of childhood diabetes in many developed countries.