Nowadays, you could not turn on a radio or television without hearing a commercial or two about the use of testosterone to enhance male sexual function and libido.  That can be true but should not be confused with enhancement of male fertility.  Testosterone is an important hormone involved in the production of sperm cells, but if taken in large amounts and for a prolonged period of time it can have the opposite effect, that is, decreased, if not complete halt  of sperm production.  Therefore, if you find yourself discussing ways to improve sexual function with your urologist, don’t forget to mention that you may also be trying to increase your fecundity, in which case testosterone may not be your best choice of medication.  Similarly, when you visit a fertility specialist don’t forget to mention the use of testosterone or any male enhancing substances (including vitamins, herbs, etc.) as they can have a negative effect on sperm count and decrease the odds of conception.  There are prescribed medications that can increase your natural production of testosterone and other medications to treat erectile dysfunction without interfering with testosterone production.  The closest analogy to a men taking large doses of testosterone and trying to have a baby would be a woman taking birth control pills and trying to do the same.