Not able meet target enrollment.

Obesity is associated with an increase in blood levels of estrogen. Estrogen or "female hormone" is believed to have a negative effect on sperm production. Aromatase inhibitors such as anastrozole work to decrease the production of estrogen and increase testosterone in the body. By decreasing the level of estrogen, sperm production should improve. In this study, the investigators will try to determine the benefit of anastrozole in obese men and follow pregnancy outcomes.

Inclusion Criteria:

1. Male partner of a couple presenting for infertility work up after one year of unprotected intercourse
2. Moderate oligozoospermia (defined as mean sperm count ≤ 20 × 106/mL and ≥ than 3 × 106/mL) of at least two separate occasions spanning a minimum of two weeks
3. Obese men BMI ≥ 30
4. FSH and LH levels < 10 mIU/mL

Exclusion Criteria:

1. Severe Oligozoospermia: Sperm count < than 3 × 106/mL, including azoospermia
2. Age less than 18 or greater than 65 years
3. Pyospermia or leukospermia: defined by white blood cells ≥ 1 million leukocytes per milliliter of semen
4. Cryptorchidism
5. Vasectomy reversal
6. Regular use of tobacco products
7. BMI < 30
8. Use of anabolic steroids or testosterone replacement
9. All patients with abnormal initial liver function tests "AST or ALT" will be excluded form the study