The influence of maternal age on Down syndrome Children born to older parents are at greater risk of genetic abnormalities, such as Down syndrome. No one knows what causes the chromosomal abnormality that causes Down syndrome, a condition that affects 1 in 800 to 1,000 children in the United States, according to the National Association for Down Syndrome. Any woman, regardless of her culture, race, and socioeconomic status, can have a baby with Down syndrome. However, the mother's age appears to be a unifying factor among children with Down syndrome. Older women are more likely to give birth to a baby with Down syndrome, and the risks increase with each passing year. The National Down Syndrome Association estimates that the chance of having a child with Down syndrome is as follows: Less than 1 in 1,000 for a woman under age 30 About 1 in 400 for a woman age 35 About 1 in 105 for a 40-year-old woman Year-old womanAbout 1 in 20 for a 46-year-old womanHistory of Down SyndromeIn 1886, physician John Langdon Down was the first scientist to identify Down syndrome. Down was the administrator of a children's mental institution in Surrey, England. From his observations and work at the institute, he was able to identify a group of children who exhibited characteristics such as a short nose, wide, flat face, and short, broad hands, which are characteristics commonly identified with Down syndrome. He later wrote an essay titled “Remarks on the Ethnic Classification of Idiots” in which he stated the idea that it was possible to classify different types of health conditions by race. His essay included his now famous classification of what is now known as Down syndrome, which he classified as Mongolian syndrome… half of paper… 1994;330:1114–8.16. American College of Medical Genetics Committee on Clinical Practice. ACMG position statement on multiple marker screening in women aged 35 years and older. American College of Medical Genetics College Newsletter, January 1994;2.17. American College of Medical Genetics Committee on Clinical Practice. Statement on multiple marker screening in pregnant women. American College of Medical Genetics College Newsletter, January 1996;6.18. American College of Obstetricians and Gynecologists. Maternal serum screening. ACOG Educational Bulletin, 1996; NO. 228.19. Benn PA, Borgida A, Horne D, Briganti S, Collins R, Rodis J. Down syndrome and neural tube defect screening: the value of using gestational age by ultrasound. Am J Obstet Gynecol. 1997;176:1056–61.20. Benacerraf BR. Ultrasound of fetal syndromes. New York: Churchill Livingstone, 1998:328–38.