At least 97% of men with cystic fibrosis are infertile, but not impotent. They make normal sperm, but are missing the vas deferens, the tube connecting the testes to the ejaculatory ducts in the penis. They can have children with assisted reproductive techniques.
Many men found to have congenital absence of the vas deferens during evaluation for infertility have a mild, previously undiagnosed form of CF.
Some women have fertility difficulties due to thickened cervical mucus or malnutrition.
Under Living with CF people who are thinking of having children can find more info on things to consider if you to become pregnant.