Retrograde ejaculation
In males, retrograde ejaculation occurs when the fluid to be ejaculated which would normally exit via the urethra is redirected towards the urinary bladder.
This may cause a couple to experience problems such as infertility, as most sperm do not get to the vagina and the rest of the female reproductive system.
As a method to induce pregnancy, the retrograde ejaculator's urine is centrifuged and the isolated sperm is then injected into the woman.
In the past, in couples where the male has had retrograde ejaculation, the man has urinated into his wife's vagina in an attempt to conceive.
Some fields of alternative medicine actually recommend and teach retrograde ejaculation as a way of "conserving the body's energy" or "conserving sperm". However, there is no scientific basis for this, as the retrograde-ejaculated sperm are simply urinated away at the next urination. Doctors do not recommend learning how to perform retrograde ejaculation, as once learnt, the habit may be hard to unlearn.