Semen samples obtained via sexual intercourse contain *** more sperm, with sperm having a slightly higher[23] motility and slightly more normal[23] morphology, compared with semen samples obtained via masturbation.Sexual intercourse also generates a 25–45%[23] increase in ejaculate volume, mainly by increased prostate[24] secretion.
This intercourse advantage is even greater for men with oligospermia.[23]
However, the single factor or factors for the intercourse advantage have not yet been isolated.It cannot be explained by presence of visual perception of physical attractiveness alone during stimulation,[23][25] although there may be a slight correlation.[26] Neither does any substantial fluctuations in sex hormones explain the intercourse advantage.[24] It is hypothesized that sexual intercourse subdues an inhibition from the central nervous system,[23] but what, in turn, is the subduing factor is still not completely known.
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