Other organ systems are also affected by cystic fibrosis. Women with CF have reduced fertility but may become pregnant and bear children normally. Nearly all men with CF are infertile due to a blockage of the sperm ducts by thickened mucus which results in sperm being unable to leave the testes. People with cystic fibrosis lose a lot of salt in their sweat, leading to problems when exercising in hot weather with heat exhaustion. Sinus infections are also common.
Cystic fibrosis is an inherited condition.
The bacteria that cause infections in the lungs of people with CF do not generally infect people with normal lungs. To develop cystic fibrosis, a person must inherit two copies of the CF gene, one from each parent. Having only one copy of the CF gene means you are a carrier. About 1 in 25 people are carriers of the gene, are perfectly healthy and do not have the disease. Children with CF are born to parents who both carry the gene without ever being aware that they were carriers of this condition.