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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]
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.
The 1990s saw significant development in research on male infertility, with reliable results indicating a decline. A 1992 Danish meta-analysis, commonly known as the Carlsen study after its principal author, showed that between 1938 and 1990 a population described as healthy had experienced a significant decrease in sperm count and semen volume.
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.
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.
The male reproductive system contains two main divisions: the testicles where sperm are produced, and the penis where semen is ejaculated through the urethra. In humans, both of these organs are outside the abdominal cavity. Having the testicles outside the abdomen facilitates temperature regulation of the sperm, which require specific ...
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]