CFTR Gene and Fertility: How This Mutation Affects Reproduction

When we talk about the CFTR gene, a gene that controls the movement of salt and water in and out of cells. Also known as cystic fibrosis transmembrane conductance regulator, it plays a critical role in producing mucus, sweat, and digestive fluids. When this gene mutates, it doesn’t just cause cystic fibrosis—it can also block fertility, especially in men. About 98% of men born with two faulty copies of the CFTR gene are infertile, not because they don’t produce sperm, but because the tubes that carry sperm are missing or blocked from birth. This isn’t rare—it’s the most common genetic cause of male infertility.

The cystic fibrosis, a life-limiting genetic disorder caused by CFTR mutations doesn’t always mean obvious symptoms. Some people carry just one copy of the mutation and never develop lung or digestive problems. But even as carriers, they can pass it on. If both parents are carriers, there’s a 1 in 4 chance their child will have cystic fibrosis—and a high chance their son will face fertility issues. That’s why genetic testing before trying to conceive is becoming standard, especially for couples with a family history or unexplained infertility.

For men with CF, sperm production often works fine, but the path out is gone. The male infertility, the inability to father a child due to biological factors here isn’t about low count or poor motility—it’s anatomical. But modern medicine has answers. Procedures like testicular sperm extraction (TESE) can pull sperm directly from the testicle, and then IVF with ICSI can make conception possible. Many couples have had healthy babies this way. It’s not guaranteed, but it’s a real path forward.

Women with CF or CFTR mutations can also face challenges. Thicker cervical mucus can make it harder for sperm to reach the egg. Some women with CF have irregular cycles or delayed puberty due to low body weight or chronic illness. But unlike men, most women with CF are still fertile. The bigger risk? Passing the mutation to their child. That’s why carrier screening for both partners is so important—if one has CF, the other should be tested before pregnancy.

And it’s not just about having kids. The genetic carrier, a person who carries one copy of a recessive gene mutation without showing symptoms status affects family planning decisions for years. Many people don’t know they’re carriers until they try to conceive—or until their child is diagnosed. That’s why more clinics now offer expanded carrier panels, checking for dozens of conditions including CFTR mutations, even if there’s no family history.

If you’re trying to get pregnant and have a history of CF, unexplained infertility, or recurrent miscarriages, ask about CFTR testing. It’s simple, cheap, and can change your entire plan. You might find out you’re a carrier. You might find out your partner is too. Or you might find out your infertility has a clear cause—and a clear solution.

Below, you’ll find detailed comparisons of treatments, testing options, and real-world experiences from people who’ve navigated CFTR-related fertility challenges. These aren’t just medical guides—they’re practical roadmaps for couples who want to build a family despite the odds.