What is the risk for having children with a problem when parents are close blood relatives?
If parents are unrelated, their risk for having a child with a birth defect or disability is 2- 3% (2-3 babies out of 100 babies born).
If parents are first cousins, the risk is a little higher at 5-6%. This is due to the increased chance that they both carry the same autosomal recessive gene alteration passed down through the family. Consequently, the risk of having a child with a birth defect or disability may be significantly higher. The risk in this situation has to be worked out for each family during Genetic Counselling.
Genetic conditions are inherited in different ways. Consanguineous parents do not have an increased risk of having a child with a dominant or X-linked condition.
Please click on the following links to find out more about genetics in with individuals that have marriages within their family.