Sudden illness, infections, prolonged fever, injury to the testes, exposure to industrial or environmental toxins, use of anabolic steroids, drug use, and alcohol intake may cause variations in sperm quality.

Do you want to make sure you have a healthy lifestyle that maximizes your fertility?

Here's a quick checklist of healthy lifestyle habits that are known to have a positive impact on fertility.

12 Keys to a Healthy Fertile Lifestyle

I have a healthy diet - fruits, vegetables, low fat, plenty of water
I am within my ideal weight range/body mass index
I live a well-balanced life that allows for rest and relaxation
I get a good night's sleep every night
I never consume excessive amounts of alcohol and drink in moderation
I exercise regularly but not excessively
I don't smoke
I don't rely heavily on over-the-counter (un-prescribed) medications
I don't use street drugs (marijuana, cocaine, etc.)
I don't use anabolic steroids
We have sexual intercourse frequently without lubricants

Helpful Tips:

Men may want to consider: wearing loose underwear (tight underwear raises the temperature around the testicles); avoid extremely hot baths, saunas, and soaking in hot tubs; and avoid smoking. Use of some vaginal lubricants may have an affect on sperm quality, as will the use of some prescription drugs.

Additionally, hereditary and hormonal disorders or hormonal problems such as diabetes, a thyroid condition, or prolactin problems, may also contribute to male factor infertility.