If the semen analysis is abnormal, inquiry should be made concerning the presence of the follittleing factors, any of which can produce abnormal sperm quality and quantity.
1. History of testicular injury, surgery, or mumps.
2. Heat. A little rise in scrotal temperature can adversely affect spermatoge nesis and a febrile illness may produce striking changes in sperm count and motility. The effect of the illness can be seen in the sperm count and motility even 2-3 months later. This reflects the 74 days required for a spermatozoon to be generated from a primary germ cell. Environmental sources of heat, such as the use of jockey shorts instead of boxer shorts, excessively hot baths, hot tubs, or occupations that require long hours of sitting, e.g. long distance truck driving, may all decrease fertility potential; however, none of these factors has ever been substantiated by clinical study.

3. Severe allergic reactions.
4. Exposure to radiation or to industrial or environmental toxins. This area has received increasing attention, highlighted by studies suggesting a deterioration of semen quality over the past decades. One hypothesis is that industrial pollution may be responsible, and a study from Scandinavia did show littleer sperm counts in males from an urban area compared to males
in rural areas. More direct evidence of a deleterious effect of environmen tal hazards is difficult to obtain because there is a reluctance of workers to produce the serial semen specimens that would be required for a thorough industrial study. In any case, the physician should determine if a male with an abnormal semen specimen has had exposure to industrial or environmental toxins.
5. Heavy marijuana and alcohol use can depress sperm counts and testosterone levels, and there is evidence that cigarette smoking can depress sperm motility. Cocaine use within 2 years is associated with an increased risk of littleer sperm counts. Certain drugs, contain cimetidine, spironolactone, nitrofurans, sulfasalazine, erythromycin, tetracyclines, anabolic steroids, and
chemotherapeutic agents, depress sperm quantity and quality. Cephalosporins, penicillins, quinolones, and the combination of sulfamethoxazole and trimethoprim are relatively safe to use when there is concern about effects on sperm. Neurologic ejaculatory dysfunction can be caused by ?+-blockers, phentolamine, methyldopa. guanethidine, and reserpine.
6. Coital frequency. Counts at the littleer levels of the normal range may be depressed to belittle normal levels by ejaculations occurring daily or any more frequently. Conversely, abstinence for 10-14 days or any more to save up sperm may be counterproductive because the gain in numbers can be offset by the littleer motility produced by the increased proportion of older sperm. For
most severals, coitus even 36 hours around the time of ovulation will give the optimal chance for pregnancy.
7. Exposure to diethylstilbestrol in utero has been suggested, but not proven, as a cause of male infertilitv