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By the 2010s, it was clear that there had been a significant, steady decline in sperm count and semen volume. A 2017 meta-analysis led by Hagai Levine from the Hebrew University reported decreases in sperm concentration of 52.4 percent and in sperm count of 59.3 percent, from 1973 to 2011 in Western countries (Australia, New Zealand, Europe ...
Sperm count declines with age, with men aged 50–80 years producing sperm at an average rate of 75% compared with men aged 20–50 years. However, an even larger difference is seen in how many of the seminiferous tubules in the testes contain mature sperm: In males 20–39 years old, 90% of the seminiferous tubules contain mature sperm.
To get that value, two different variables are multiplied: sperm concentration—the number of sperm per millimeter of semen—and semen volume, which is exactly what it sounds like.
Males from India had a 30.3% decline in sperm count, 22.9% decline in sperm motility, and a 51% decrease in morphology over a span of a decade. Doctors in India disclosed that the sperm count of a fertile Indian male had decreased by a third over a span of three decades. [80]
Collecting the sperm at home gives a higher sperm concentration, sperm count, and motility, particularly if the sperm is collected via sexual intercourse. [35] If the semen sample is to be collected by masturbation, a specimen from the early stages of the ejaculation should be placed into a clean, unused, sealed collection cup.
A 1992 World Health Organization report described normal human semen as having a volume of 2 mL or greater, pH of 7.2 to 8.0, sperm concentration of 20×10 6 spermatozoa/mL or more, sperm count of 40×10 6 spermatozoa per ejaculate or more, and motility of 50% or more with forward progression (categories a and b) of 25% or more with rapid ...
A semen analysis (plural: semen analyses), also called seminogram or spermiogram, evaluates certain characteristics of a male's semen and the sperm contained therein. [ 1 ] [ 2 ] [ 3 ] It is done to help evaluate male fertility , whether for those seeking pregnancy or verifying the success of vasectomy .
For example, males who are at a higher risk of sperm competition (defined as having female partners with high reproductive value, such as being younger and physically attractive) engaged more frequently in semen-displacing behaviors during sexual intercourse than men who were at a lower risk of sperm competition. [22]