1. Genetic mutations: Congenital bilateral absence of the vas deferens (CBAVD) is usually caused by genetic mutations in the CFTR gene, which is responsible for the production of a protein that helps regulate the movement of salt and water in and out of cells.
2. Cystic Fibrosis: CBAVD is often associated with cystic fibrosis, a genetic disorder that affects the lungs, pancreas, and other organs.
3. Unknown Causes: In some cases, the cause of CBAVD is unknown.