If a man has a hernia, does it eliminate or reduce his possibilities of impregnating a woman?

An inguinal hernia is where a loop of the small intestine travels through the inguinal canal and can go as far as the scrotum. This often only happens on one side, so although the pressure of the intestine pushing on the vas defrans could keep the semen from flowing into the prostatic urethra, the other side would be working fine and millions of sperm would still be getting out in every ejaculate. So in answer to your question it does not eliminate it, but it may slightly reduce it.

Lol, no, a Hernia is just a tear of a "tissue" like object.

However if the Hernia is "devastating" in the lower scrotum area, it seriously needs to be repaired so the male can function normally and work, as this is a very, very bad condition, not to mention PAINFUL.

Nope -- everything works as usual. Speaking from experience.