What Every Expectant Couple Needs to Know About Genetics (Part 2)

Many genetic diseases occur more frequently in people of certain ethnic backgrounds. That is why it is important to understand how your ethnic background affects your risk to have a child with a genetic disease.

For example, sickle cell disease occurs more commonly in African-Americans, Tay-Sachs disease in people of Ashkenazi (eastern and central European) ancestry, thalassemia in people of Middle Eastern and Mediterranean descent and cystic fibrosis in Caucasians.

Many of these ethnic-based genetic diseases are inherited in an autosomal recessive pattern. This means that two copies of a mutated gene, one from each parent, are necessary to cause the disorder.

People with only one copy of a mutated gene are known as carriers. In most autosomal recessive conditions, carriers do not have any symptoms of the condition and, therefore, are often unaware that they are a carrier until they have a positive carrier test or have an affected child.

The risk of having a child with these genetic diseases is based on the inheritance pattern, as well as both of the parent’s ethnic backgrounds. Couples who are of the same ethnic background may have a higher risk of having a child with autosomal recessive disorders than couples who are of different ethnic backgrounds.

  • Couples who are also related to each other by blood, such as cousins, may have an even higher risk.
  • A family history of a disorder can also further increase the risk to have an affected child.


Understanding your risk to have an affected child is the first step to making an informed decision about carrier testing before or during your pregnancy. To better understand your risk, you can use our Family Health History tool to analyze your ethnic background and family health history.

Published on: November 19, 2010
About the Author
Photo of Jordanna Joaquina MS CGC

Jordanna Joaquina, MS, CGC is a board certified genetic counselor. She is also Co-founder and Director of Genetics of Inherited Health, an online secure resource that combines family health history and hereditary disease risk assessment. Inherited Health helps families take steps to lower their disease risks together.

Get Dr. Greene's Wellness RecommendationsSignup now to get Dr. Greene's healing philosophy, insight into medical trends, parenting tips, seasonal highlights, and health news delivered to your inbox every month.