Which reproductive structure is typically absent in males with cystic fibrosis, contributing to infertility?

• A. Vas deferens
• B. Epididymis
• C. Seminal vesicles
• D. Testes

Answer: (A)

In males with cystic fibrosis, the vas deferens is often absent due to congenital bilateral absence of the vas deferens (CBAVD). The vas deferens normally carries sperm from the epididymis to the ejaculatory ducts, so when it’s missing, sperm cannot reach the semen. This creates obstructive infertility even though sperm production in the testes is typically normal. The underlying CFTR mutations disrupt development of Wolffian duct derivatives during embryogenesis, leading to this absent structure. The epididymis and testes are usually present and functional, and while seminal vesicles can be variably affected, the key factor in infertility is the lack of the vas deferens. In many cases, sperm can still be retrieved from the testes or epididymis for assisted reproductive techniques like IVF with ICSI.