Mayo Clinic: Men’s Health Center


Cystic fibrosis (CF) is a genetic condition that causes severe damage to the lungs, digestive system and other organs in the body. It affects approximately 30,000 people in the United States and can be associated with male infertility. An estimated 10 million people in the United States are carriers of cystic fibrosis, which means that they have the gene for CF, even though they have no symptoms.

To have CF, you must inherit a copy of the cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation from each parent. People who have only one copy of a CFTR gene mutation do not have CF. They are called "CF carriers".

Almost all men with CF are infertile because the tube that connects the testes and prostate gland (vas deferens) is either blocked with mucus or missing entirely. Certain fertility treatments and surgical procedures sometimes make it possible for men with CF to become biological fathers.

Why it's done

Your doctor may recommend performing cystic fibrosis gene testing if you are being seen for low sperm counts and have a family history of cystic fibrosis or are missing a vas deferens (tube that carries sperm from testicle to the ejaculate) on physical exam.


A cystic fibrosis gene test has little physical risk. When the needle is inserted to draw blood, some people may feel some pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise.

A cystic fibrosis gene test can have emotional, social and financial risks as well. Discuss all risks and benefits of genetic testing with your doctor, a medical geneticist or a genetic counselor before you have a genetic test.

How to prepare

There is nothing that you need to do ahead of time. You do not need to be fasting when the labs are drawn.


Men who are diagnosed with CF may still be able to father children, but they may have to undergo sperm retrieval directly from the testicle (a procedure called testicular sperm extraction) . The sperm retrieved may then be used for in-vitro fertilization.

If you are a CF carrier, your partner should also be tested to see what your risk is of having a child with CF. If you or your partner are carriers, you should consider meeting with a medical geneticist or genetic counselor to discuss the emotional, social, and financial implications.

Did you know?

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