It is nearly impossible for a man to retain his ability to father children through sexual intercourse after initial treatment.
 
During prostatectomy, both the prostate and the nearby seminal vesicles are removed. Seminal vesicles and the prostate provide semen that carries the sperm down the urethra and out the penis during ejaculation. The loss of semen following surgery makes ejaculation impossible, so the sperm cannot physically leave the body.
 
Radiation therapy nearly always impairs fertility. Radiated prostate cells and seminal vesicles tend to produce semen that cannot transport the sperm well. Sperm can also be damaged, though this occurs far less frequently with more accurate dose planning.

Post-Treatment Fertility Options

For men who wish to father children after treatment for prostate cancer, the best chance for fertility is sperm banking. Semen containing sperm is frozen in liquid nitrogen. After thawing, up to 50% of sperm will regenerate and can be used for artificial insemination.
 
Extracting sperm directly from the testicles might be another option. After harvesting sperm from testicular tissue, a single microscopic sperm is injected into a single microscopic egg. If an embryo forms, it is implanted into the woman’s uterine wall and allowed to grow.
 
The success rates for the two procedures combined—sperm extraction followed by injection of the sperm into the egg—is less than 50%.