Genetic Testing

Recessive genetic diseases are those that result from abnormal recessive genes. A child who inherits an abnormal gene from both biological parents will have the disease. A child who inherits the abnormal gene from only one biological parent will be a carrier for the disease. Carriers do not usually exhibit symptoms of the disease, but they can pass the carrier gene on to their own offspring. A child whose biological parents are both carriers for a recessive disease has a 25% chance of inheriting the abnormal gene from both biological parents and being born with the disease; a 25% chance of inheriting no abnormal genes; and a 50% chance of inheriting one abnormal gene and becoming a carrier. If only one biological parent is a carrier, the child has no chance of being born with the disease, but has a 50% chance of being a carrier.


If a TSBC program donor is found to be a carrier for any of the following recessive diseases, he is not accepted and we do not release any of his semen samples. We recommend that directed donors be screened for these diseases, as applicable. If a directed donor is found to be a carrier, we would recommend that his recipient be tested to determine her own carrier status. We will release the directed donor’s semen samples provided his recipient has been informed of the potential risk.

Cystic Fibrosis

Cystic fibrosis (CF) is a debilitating lung disease that usually results in chronic respiratory infections and shortened life expectancy. CF primarily affects white people of Northern European ancestry. One in twenty-five Northern Europeans are carriers, while the odds of members of other ethnic groups being carriers are considerably lower, but unknown. At TSBC, we screen all our program donors for cystic fibrosis, regardless of their ethnic heritage, and we recommend that all directed donors and/or their recipients be screened as well.

Tay Sachs

Tay Sachs is a disorder in which an enzyme deficiency results in the progressive destruction of brain and nerve cells, leading to neurological damage and death before the age of five. While it is quite rare in the general population, it occurs in about one in 3,600 infants of Ashkenazi (Eastern European) Jewish, Cajun, or French Canadian ancestry. At TSBC, we screen all our program donors of Jewish, Cajun, or French Canadian descent for Tay Sachs.

Sickle cell disease and Thalassemia

Sickle cell disease is an inherited form of anemia that leads to blocked blood flow, susceptibility to infection and stroke, and organ damage. It is found almost exclusively in individuals of African descent and affects about one in 400 African-Americans. The thalassemias are a group of inherited anemias that affect individuals of African, Asian, and Mediterranean descent. They are caused by an imbalance in the production of hemoglobin, and symptoms range in severity from mild anemia to the need for frequent blood transfusions and possible heart failure. At TSBC, we screen all our program donors for sickle cell and thalassemia regardless of their ethnic heritage—the hemoglobin electrophoresis test screens for both traits.

Other Carrier Traits

If a recipient asks us to screen a program donor or directed donor for carrier traits not listed above, we will make every effort to have our lab do the requested testing. In these instances we will charge the recipient for the additional lab fee.