Wolffian ducts are present in all embryos in early development. In males, the Wolffian ducts typically develop into the vas deferens, the epididymis, and the seminal vesicles. The vas deferens is the passageway that carries sperm from the epididymis to the ejaculatory duct. The epididymis is an organ located on the testes that has passageways (ducts) that carry sperm from the testes to the vas deferens. The seminal vesicles are glands that produce the fluid component of semen. In females, the Wolffian ducts typically regress (disappear) before birth.