About 30,000 Americans havecystic fibrosis(CF), a genetic disorder that primarily affects the lungs and digestive system.
Verywell / Jessica Olah
10 Million Americans Are CF Carriers
Cystic fibrosis is most common among people of European descent. It affects 1 in 3,500 live births of European Americans in the United States, but only 1 in 17,000 live births among African Americans, 1 in 4,000 to 1 in 10,000 live births among Hispanics, and 1 in 31,000 live births among Asian Americans.
Although CF is rare, being a CF carrier is relatively common. In the United States, 1 out of every 31 people is a CF carrier.As with CF, the carrier rate is highest among people of European descent and lower among people of other ethnic groups.
If no one in your family has CF, your chance of being a carrier depends on your ethnic background, such as:
Carrier Status: Genetic Testing
Genetic testing can tell you if you are a CF carrier. Genetic tests look at your DNA (genetic material). Your DNA is extracted either from a blood sample or from a swab of the cells inside your mouth and analyzed for common CF-causing mutations.
The standard genetic test for CF looks for the 23 most common CF-causing mutations in the CFTR gene. The exact mutations screened for in the test will depend on your ethnic background and family history. If you have a relative with CF or who is a known carrier, you have a greater chance of also being a carrier.
Who Should Get Tested?
Because being a CF carrier does not typically cause symptoms, most people are unaware they are carriers unless they are tested.
Getting tested for CF is a personal choice. The American College of Obstetricians and Gynecologists (ACOG) recommends physicians offer prenatal genetic screening for CF and other genetic conditions to anyone planning to become pregnant or are already pregnant.People with Ashkenazi Jewish or European ancestry have the highest chances of being a carrier.
If you have a child with CF, all the child’s siblings should be tested for CF, regardless of whether they have symptoms. Your other relatives may also wish to be screened to see if they carry a CF-causing mutation.
Interpreting Your Test Results
If your screening test comes back positive, you have an over 99% chance of carrying a defective CFTR gene.
If your test comes back negative, you do not carry one of the common mutations that lead to CF. It is still possible, although unlikely, that you carry a rare mutation not screened for. Research has identified over 1,700 different mutations that can cause CF—but most of these mutations are extremely rare.
Testing for these rare mutations may be warranted if your partner has a CF-causing mutation, or if you have a family member who is a CF carrier. Be sure your doctor is aware of your family history and any concerns you might have.
Children of Carriers May Be at Risk
Cystic Fibrosis Testing During Pregnancy
Higher Likelihood of CF-Related Health Conditions
Because CF carriers have one functioning copy of the CFTR gene, they do not have cystic fibrosis, and generally do not experience any symptoms of the disease.
Recent research, however, has found that CF carriers do face certain elevated health risks compared to noncarriers. These health risks are a milder form of those seen in people with CF, and include:
Notably, these health risks and associated symptoms are quite mild compared with CF—a chronic condition that requires hours of daily management and significantly shortens the lifespan. For example, a person with CF needs nutritional supplements from birth due to pancreatic insufficiency, whereas a CF carrier has a slightly elevated, but still less than one in a hundred, risk of developing pancreatitis. Most CF carriers will not experience any of these health problems.
A Word From Verywell
Being a cystic fibrosis carrier is very common. It is not typically linked with any symptoms or health problems, although being a carrier can slightly raise your risk of certain conditions, like male infertility and pancreatitis (inflammation of the pancreas). Talk with your healthcare provider if you have concerns about how being a CF carrier is impacting your health.
Frequently Asked QuestionsCystic fibrosis is a serious, life-threatening disorder that primarily affects the lungs and the pancreas. It causes chronic lung infections and a progressive decline in lung function that shortens the lifespan. Advances in treatment have greatly improved survival of people with CF. Only a few decades ago, most died in childhood. Today, babies born with CF can expect to live into their 40s and 50s.Learn MoreCystic Fibrosis SymptomsNearly all men with CF (97%–98%) are born with a condition known as congenital bilateral absence of the vas deferens (CBAVD). They lack the canals through which the sperm pass into the semen and, therefore, cannot fertilize an egg via intercourse. Because these men do produce sperm, they can often have biological children with assisted reproductive procedures involving sperm extraction.Women with CF are fertile, but they may have reduced fertility because of thicker than normal cervical mucus and ovulation issues related to poor nutrition.Women who are carriers have normal fertility. Men who are carriers may occasionally have reduced sperm quality or have the same congenital defect seen in men with CF: congenital bilateral absence of the vas deferens (absence of the sperm canals).For men with this congenital defect, because their semen does not contain sperm, they cannot conceive via intercourse. But because they do produce sperm, they can often have children with assisted reproductive techniques.
Frequently Asked Questions
Cystic fibrosis is a serious, life-threatening disorder that primarily affects the lungs and the pancreas. It causes chronic lung infections and a progressive decline in lung function that shortens the lifespan. Advances in treatment have greatly improved survival of people with CF. Only a few decades ago, most died in childhood. Today, babies born with CF can expect to live into their 40s and 50s.Learn MoreCystic Fibrosis Symptoms
Cystic fibrosis is a serious, life-threatening disorder that primarily affects the lungs and the pancreas. It causes chronic lung infections and a progressive decline in lung function that shortens the lifespan. Advances in treatment have greatly improved survival of people with CF. Only a few decades ago, most died in childhood. Today, babies born with CF can expect to live into their 40s and 50s.
Learn MoreCystic Fibrosis Symptoms
Nearly all men with CF (97%–98%) are born with a condition known as congenital bilateral absence of the vas deferens (CBAVD). They lack the canals through which the sperm pass into the semen and, therefore, cannot fertilize an egg via intercourse. Because these men do produce sperm, they can often have biological children with assisted reproductive procedures involving sperm extraction.Women with CF are fertile, but they may have reduced fertility because of thicker than normal cervical mucus and ovulation issues related to poor nutrition.
Women who are carriers have normal fertility. Men who are carriers may occasionally have reduced sperm quality or have the same congenital defect seen in men with CF: congenital bilateral absence of the vas deferens (absence of the sperm canals).For men with this congenital defect, because their semen does not contain sperm, they cannot conceive via intercourse. But because they do produce sperm, they can often have children with assisted reproductive techniques.
11 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Sanders DB, Fink AK.Background and Epidemiology.Pediatr Clin North Am. 2016;63(4):567-584. doi:10.1016/j.pcl.2016.04.001Cystic-Fibrosis.com.How Common is Cystic Fibrosis?UCSF Health.Carrier Testing for Cystic Fibrosis FAQ.Cystic Fibrosis Foundation.Carrier Testing for Cystic Fibrosis.American College of Obstetricians and Gynecologists.FAQ. Cystic Fibrosis: Prenatal Screening and Diagnosis.familydoctor.org.Cystic Fibrosis Prenatal Screening and Diagnosis.Cystic Fibrosis Foundation.Newborn Screening for CF.Miller AC, Comellas AP, Hornick DB, et al.Cystic fibrosis carriers are at increased risk for a wide range of cystic fibrosis-related conditions.Proc Natl Acad Sci U S A. 2020;117(3):1621-1627. doi:10.1073/pnas.1914912117McCallum TJ, Milunsky JM, Cunningham DL, Harris DH, Maher TA, Oates RD.Fertility in men with cystic fibrosis: an update on current surgical practices and outcomes.Chest. 2000;118(4):1059-1062. doi:10.1378/chest.118.4.1059Cystic Fibrosis Foundation.Fertility in Women With CF.van der Ven K, Messer L, van der Ven H, Jeyendran RS, Ober C.Cystic fibrosis mutation screening in healthy men with reduced sperm quality.Hum Reprod. 1996;11(3):513-517. doi:10.1093/humrep/11.3.513
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Sanders DB, Fink AK.Background and Epidemiology.Pediatr Clin North Am. 2016;63(4):567-584. doi:10.1016/j.pcl.2016.04.001Cystic-Fibrosis.com.How Common is Cystic Fibrosis?UCSF Health.Carrier Testing for Cystic Fibrosis FAQ.Cystic Fibrosis Foundation.Carrier Testing for Cystic Fibrosis.American College of Obstetricians and Gynecologists.FAQ. Cystic Fibrosis: Prenatal Screening and Diagnosis.familydoctor.org.Cystic Fibrosis Prenatal Screening and Diagnosis.Cystic Fibrosis Foundation.Newborn Screening for CF.Miller AC, Comellas AP, Hornick DB, et al.Cystic fibrosis carriers are at increased risk for a wide range of cystic fibrosis-related conditions.Proc Natl Acad Sci U S A. 2020;117(3):1621-1627. doi:10.1073/pnas.1914912117McCallum TJ, Milunsky JM, Cunningham DL, Harris DH, Maher TA, Oates RD.Fertility in men with cystic fibrosis: an update on current surgical practices and outcomes.Chest. 2000;118(4):1059-1062. doi:10.1378/chest.118.4.1059Cystic Fibrosis Foundation.Fertility in Women With CF.van der Ven K, Messer L, van der Ven H, Jeyendran RS, Ober C.Cystic fibrosis mutation screening in healthy men with reduced sperm quality.Hum Reprod. 1996;11(3):513-517. doi:10.1093/humrep/11.3.513
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Sanders DB, Fink AK.Background and Epidemiology.Pediatr Clin North Am. 2016;63(4):567-584. doi:10.1016/j.pcl.2016.04.001Cystic-Fibrosis.com.How Common is Cystic Fibrosis?UCSF Health.Carrier Testing for Cystic Fibrosis FAQ.Cystic Fibrosis Foundation.Carrier Testing for Cystic Fibrosis.American College of Obstetricians and Gynecologists.FAQ. Cystic Fibrosis: Prenatal Screening and Diagnosis.familydoctor.org.Cystic Fibrosis Prenatal Screening and Diagnosis.Cystic Fibrosis Foundation.Newborn Screening for CF.Miller AC, Comellas AP, Hornick DB, et al.Cystic fibrosis carriers are at increased risk for a wide range of cystic fibrosis-related conditions.Proc Natl Acad Sci U S A. 2020;117(3):1621-1627. doi:10.1073/pnas.1914912117McCallum TJ, Milunsky JM, Cunningham DL, Harris DH, Maher TA, Oates RD.Fertility in men with cystic fibrosis: an update on current surgical practices and outcomes.Chest. 2000;118(4):1059-1062. doi:10.1378/chest.118.4.1059Cystic Fibrosis Foundation.Fertility in Women With CF.van der Ven K, Messer L, van der Ven H, Jeyendran RS, Ober C.Cystic fibrosis mutation screening in healthy men with reduced sperm quality.Hum Reprod. 1996;11(3):513-517. doi:10.1093/humrep/11.3.513
Sanders DB, Fink AK.Background and Epidemiology.Pediatr Clin North Am. 2016;63(4):567-584. doi:10.1016/j.pcl.2016.04.001
Cystic-Fibrosis.com.How Common is Cystic Fibrosis?
UCSF Health.Carrier Testing for Cystic Fibrosis FAQ.
Cystic Fibrosis Foundation.Carrier Testing for Cystic Fibrosis.
American College of Obstetricians and Gynecologists.FAQ. Cystic Fibrosis: Prenatal Screening and Diagnosis.
familydoctor.org.Cystic Fibrosis Prenatal Screening and Diagnosis.
Cystic Fibrosis Foundation.Newborn Screening for CF.
Miller AC, Comellas AP, Hornick DB, et al.Cystic fibrosis carriers are at increased risk for a wide range of cystic fibrosis-related conditions.Proc Natl Acad Sci U S A. 2020;117(3):1621-1627. doi:10.1073/pnas.1914912117
McCallum TJ, Milunsky JM, Cunningham DL, Harris DH, Maher TA, Oates RD.Fertility in men with cystic fibrosis: an update on current surgical practices and outcomes.Chest. 2000;118(4):1059-1062. doi:10.1378/chest.118.4.1059
Cystic Fibrosis Foundation.Fertility in Women With CF.
van der Ven K, Messer L, van der Ven H, Jeyendran RS, Ober C.Cystic fibrosis mutation screening in healthy men with reduced sperm quality.Hum Reprod. 1996;11(3):513-517. doi:10.1093/humrep/11.3.513
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