What are the causes of ejaculatory duct obstruction?

Ejaculatory duct obstruction may be caused by any of the following:

Stones
Infections of the prostate
Urologic surgery via the prostate
Congenital cysts
Congenital abnormalities of the vas deferens
Other causes

   Pseudo ejaculatory duct obstruction can be said to occur when the semen goes backwards into the bladder. This disorder is caused by incompetent smooth musculature of the bladder neck, which usually serves as a physiologic sphincter during emission and ejaculation. This disorder, called retrograde ejaculation, is often caused by prostatic surgery for benign prostatic hyperplasia (BPH). The prostatic pressure against a constricted external sphincter preferentially diverts the ejaculate into the bladder, when the bladder neck is weakened.