In the past, people with cystic fibrosis typically died in childhood, but modern medicine has allowed men and women with cystic fibrosis to live well past puberty. Therefore, longer lifespans have produced new issues surrounding fertility. Unfortunately, almost all males with cystic fibrosis are infertile. Male infertility is caused by a malformed vas deferens, which is the tube that carries sperm from the testis to the penis. This condition is called Congenital Bilateral Absence of the Vas Deferens (CBAVD). A minority of men with cystic fibrosis do not experience infertility. These are men with the 3849-10kb C-T genetic mutation of cystic fibrosis [source: Cystic Fibrosis Medicine]. Approximately 98 percent of men with cystic fibrosis are infertile. This means that only two or three men with cystic fibrosis out of 100 have normal reproductive capabilities [source: Cystic Fibrosis Trust].
Typically, men with cystic fibrosis who want to father a child, require assisted reproduction techniques. This involves removal of the sperm from the male and insertion of the sperm into the male's partner. Unfortunately, men with cystic fibrosis tend to also have malformed sperm and low sperm counts, which complicate this procedure. Moreover, assisted reproduction techniques can be quite expensive and time consuming [source: Cystic Fibrosis Medicine].
Women with cystic fibrosis typically have difficulties with regular menstrual cycles, including missed or irregular periods, or amenorrhea, which is the absence of periods. Typically, irregular cycles are the result of low body weight, poor overall health, and poor control of cystic fibrosis-related diabetes. Women with cystic fibrosis may also have thick mucous that surrounds the cervix, making it difficult for sperm to penetrate into the uterus. Overall, these female infertility issues are relatively well-managed and most women with cystic fibrosis can get pregnant.