Genetics
CF is an autosomal recessive disorder, which means a person needs to have two copies of an abnormal “CF gene” in order to have the disease. People with only one copy are considered carriers and will not have CF. If one carrier reproduces with another carrier, there is a 25 percent chance that their children will have CF. However, if two people with CF reproduce, then all of the children will have CF. If someone with CF has children with someone who is not a carrier, all of the children will be carriers but none will have CF. With such high probability of passing on "abnormal CF genes," you should know your partner’s genetic makeup, which can be determined through screening tests. It is recommended that spouses of CF patients have one of the more thorough tests available to determine if they are a carrier.

Fertility
It is very important for female CF patients to realize they have relatively normal fertility and can become pregnant. Although these patients may be told that they are too sick to have children, that their children will have birth defects or there will be birth complications, this is often not true. Many women with CF will have a full-term pregnancy. Whether a woman is healthy enough to care for a child over the subsequent years is another issue that needs to be considered.  Women considering birth control should discuss their intentions with a gynecologist.

Conversely, most males with CF are infertile and cannot father children without assisted reproductive technology. Over 95 percent of boys with CF are missing the vas deferens—the tubes that connect the testes to the urethra. Sperm is produced but it cannot leave the tests. Because 5 percent of patients will not be affected, all male patients should have semen analysis to determine their fertility.

Sexually Transmitted Diseases
People with CF are susceptible to all sexually transmitted diseases (STDs) including HIV/AIDS, herpes, syphilis, gonorrhea, and chlamydia. Despite reproductive problems, male CF patients can still be infected by and spread STDs. It is important for male and female CF patients to always use protection when sexually active.

Having a Baby
For most CF patients, or those married to someone with CF, starting a family raises many questions. “Is having a baby right for me?” is at the top of the list. Because most female CF patients can complete a full-term pregnancy, CF complications like diabetes and pulmonary exacerbations need to be considered. While most CF medications are safe during pregnancy, many antibiotics for pulmonary exacerbations should not be used.

Men and women with CF need to consider whether they have the family support to care for an infant and young children. Determining whether a parent will be healthy in 5, 10, or 15 years and ensuring adequate assistance during times of illness are paramount. Patients will need to meet the demands of taking care of themselves and their child.

Future mothers with CF should discuss pregnancy with their doctors before becoming pregnant. Patients, obstetricians and CF doctors should communicate frequently before and throughout pregnancies. Maintaining good lung function and nutritional status are key during pregnancy. Pregnant CF patients must stop taking Vitamins A, D, E and K and begin taking prenatal vitamins with supplemental Vitamin E. Antibiotics such as fluoroquinolones and tetracyclines should be stopped as well. Additional screenings for diabetes and elevated blood sugars must also be provided.

Infertile male CF patients who want children have several options. Adoption is a very attractive choice for many families. Microepididymal sperm aspiration (MESA), in which a small amount of sperm is extracted from the epididymis and used for in vitro fertilization, is another. This procedure requires the mother to take hormone injections and have eggs harvested, fertilized and re-implanted. While the success rates for this procedure have improved significantly over the years, it is time consuming and expensive.