It is more common to be a carrier of a genetic disease, such as cystic fibrosis (CF), than to have the disease. If tests show that you are a carrier of a disease, your partner also should be tested. Both parents must be carriers of a disease for a child to get the disease.
The tests are not 100% accurate, so a person may test negative and yet be a carrier. If you are a carrier and your partner tests negative, there is still a very small chance that you will have a child with the disease.1
If you and your partner are both carriers of the same genetic disease, there is a 1-in-4 (25%) chance that your child will have the disease.
If you are not already pregnant, you may wish to have genetic counseling to understand your risks and options if you decide to have children.