What can shut down sperm production?

Anything that warms the testicles is going to shut down sperm production temporarily: sitting in a hot tub, for instance, or constantly using a computer (which can generate a surprising amount of heat) on your lap.

Here are some other sperm killers to watch out for:

• Medical problems such as enlarged veins in the scrotum, infections of the reproductive tract (many of which may not be noticeable) and obstructions of a man's ejaculatory ducts
• Obesity (it lowers testosterone levels)
• Poor diet
• Use of steroids to enhance athletic performance (these shut down testosterone production and halt sperm production)
• Use of lubricants during sex (most lubricants are toxic to sperm)
• Excessive smoking, alcohol use or drug use