title: Study of a group of 484 fertile men. Part II: relation between age (20-59) and semen characteristics.
abstract: Commonly measured semen variables as well as post-thaw motility have been studied as a function of age in fertile men. The mean age was 34.6 (SD = 6.6). No significant change with age was found for the sperm count, semen volume or total number of spermatozoa. Conversely, there were significant differences between age groups for the percentage of normal cells (P less than 0.01) and the percentage of motile forms (P less than 0.01) as well as for the after-thaw motility (P less than 0.001). These three variables rise, reach a maximum level at 30 to 35 years of age and then decrease. These changes are not explained by variations in the length of abstinence.
mesh_terms: D000328:Adult; D000375:Aging; D006801:Humans; D008297:Male; D008875:Middle Aged; D012661:Semen / Q000032:analysis*; D012662:Semen Preservation; D012746:Sexual Abstinence; D013076:Sperm Count; D013081:Sperm Motility