As you browse through the Donor Nexus egg donor database, you’ve likely come across several profiles that indicate that the egg donor is a genetic carrier of a certain condition. This may sound alarming to intended parents at first, which is why we are here to explain what exactly it means and what you should do if your ideal donor is a carrier. The good news is that with proper screening of the male partner or sperm provider, your child will almost certainly not inherit the genetic disease.
Before you decide not to choose a donor because she is a known carrier, it’s important to note that most of us are carriers of at least one genetic disease. We have over 20,000 genes and all it takes is a mutation in one copy of a particular gene to be a carrier of a genetic disorder.
Importantly, if a donor is a carrier, it does not mean that she is unhealthy. If a donor is listed as a carrier, it means that she has had genetic carrier screening and tested positive as a carrier for the indicated disease.
As defined by the American College of Obstetricians and Gynecologists,
“For some genetic disorders, it takes two genes for a person to have the disorder. A carrier is a person who has only one gene for a disorder. Carriers usually do not have symptoms or have only mild symptoms. They often do not know that they have a gene for a disorder.”
Genes are inherited in pairs: one from the mother (egg provider) and one from the father (sperm provider). A genetic carrier is someone who has a change, known as a mutation, in only one copy of a gene -- meaning the carrier has inherited a recessive allele for the mutation. Since the other copy of the gene is working properly, the carrier does not develop or have symptoms of the disease. Many individuals, including donors, who have taken expanded genetic screening tests will be found to be a carrier of at least one condition. Many of us are carriers and don’t even know it.
These diseases are autosomal recessive, meaning two copies of the abnormal gene must be present in order for the disease to develop. That means both the egg source and the sperm source would need to share the same gene mutation in order for the child to inherit the disease. In the rare circumstance that the egg source and sperm source are both carriers of the same disease, the risk of the child inheriting the disease is 25%. Otherwise, if only the egg donor is a carrier, there is no increased risk of the child inheriting the disease.
Of course, you only want the best for your child. As discussed, your child is not at an increased risk as long as the male partner is not a carrier of the same disease.
However, if the egg donor is a carrier, there is a 50% chance that the offspring will also be a carrier. This is not cause for too much concern, as the offspring will typically not have health issues caused by being a carrier -- just as the egg donor is perfectly healthy regardless of carrier status.
To determine potential effects of a positive carrier status, consider talking with a genetic counselor to evaluate what being a carrier of a given condition may look like.
We understand that choosing an egg donor is not an easy decision, and there are so many factors to consider. If you have found an egg donor who meets other important criteria you’ve been searching for, yet is a known positive carrier, it’s required to have your male partner or the sperm provider tested to ensure he is not a carrier. You may also consider speaking with a genetic counselor before making your decision.
If your male partner or chosen sperm prover is a carrier of the same disease, there is a 25% chance that the offspring will inherit the disease. Understandably, a one in four chance is fairly significant, so intended parents generally select a different egg donor or sperm provider (if applicable) if this is the case.
If the male partner or sperm provider does not test positive for the same disease, you can be reassured that your child does not have an increased chance of inheriting the disease.
The American Society of Reproductive Medicine states that it is not necessary to exclude the egg donor if the male partner or sperm provider has undergone appropriate carrier screening. Given that information, you should feel confident in your decision once you have done your due diligence in ensuring that your male partner or the sperm provider is not a carrier. However, it’s important to listen to your gut instinct if you are feeling uncertain and seek professional guidance from a genetic counselor to address any concerns or questions you may have.
Generally, intended parents do not rule out an egg donor based solely on her positive carrier status. We understand that choosing an egg donor is a huge decision, and if you’ve found a donor who has many of the characteristics that you’re seeking, we encourage you to have your male partner or sperm provider tested and speak with a genetic counselor before making your decision. Ultimately, you should make the decision that feels right to you and is best for your family.
Disclaimer: The information shared on this page is not medical advice. The purpose of this blog is to provide you with general information which should then be discussed with health care professionals regarding your situation.