Estradiol and male fertility.

Serum estradiol (E2) levels were measured in 451 men attending an infertility clinic and 80 fertile men attending for vasectomy. The normal range of E2 levels found in fertile men was 70 to 200 pmol/l. Subfertile men had lower mean E2 levels than fertile men (P less than 0.05), but there was no relationship to obesity, cigarette smoking, age, or the male infertility diagnostic category. E2 levels in the subfertile group gave no prognostic information concerning future fertility. The authors conclude that E2 measurements in male patients are not useful in clinical infertility practice.