Retrograde ejaculation is a condition in which semen travels back into the bladder instead of forward through the urethra.
Normally, the bladder neck closes tightly during orgasm. This prevents semen from travelling back into the bladder. The semen has nowhere to go but out of the urethra and the tip of the penis. Damage to the bladder neck or neurologic disorders may prevent it from closing properly.
The most common cause of retrograde ejaculation is transurethral resection of the prostate. This is surgical removal of prostate tissue through the urethra. Other causes include: