Deterioration of semen quality during summer in New Orleans.

A retrospective investigation of semen quality was undertaken at a fertility clinic in New Orleans. Semen specimens obtained during the summer had significantly lower sperm concentration, total sperm per ejaculate, percent motile sperm, and motile sperm concentration than samples provided at other times of year. Substantial summer deterioration in semen quality was likely to occur only among men whose work places were probably not air-conditioned. These findings suggest that the deleterious effects of summer heat on spermatogenic cells or on epididymal spermatozoa may reduce male fertility and account, at least partially, for the deficit of spring births in warm climates throughout the world.