Unlike some other genetic conditions, cystic fibrosis occurs equally as often in men and women. The genetic mutation for cystic fibrosis occurs on chromosome 7 and is not impacted by gender. The severity of symptoms related to cystic fibrosis, however, does vary in men and women. In particular, girls with cystic fibrosis have more difficulty with meeting growth milestones and experience more lung-related problems compared to boys. Due to these more severe symptoms, women with cystic fibrosis have shorter life expectancies than men. It is estimated that men with cystic fibrosis live four to five years longer than women with cystic fibrosis, Moreover, under the age of 20, girls have a 60 percent greater chance of dying due to cystic fibrosis complications compared to males [source: Cystic Fibrosis Worldwide]. As a result, the prevalence of male adults with cystic fibrosis is greater than the prevalence of female adults with cystic fibrosis, suggesting a male advantage with the disorder.
Cystic fibrosis researchers argue that this gender difference is the result of early-onset lung infections in girls. Girls appear to develop these infections earlier in life than boys, leading to more severe cystic fibrosis complications, and even death. Girls also appear to have greater difficulty maintaining a healthy body weight after puberty compared to males, which places girls at greater risk for cystic fibrosis complications. It appears that this gender gap can narrow if girls are provided with more intensive medical care. In fact, girls and women who receive regular intravenous antibiotics, regardless of their condition, have improved survival rates [source: Cystic Fibrosis Worldwide]. As a result, countries with excellent health care, such as Scandinavian countries, do not have a difference in the survival rate of men and women with cystic fibrosis.