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A 2017 review and meta-analysis found sperm counts among Western men (i.e. men in Australia, Europe, New Zealand, and North America) declined 50–60% between 1973 and 2011, with an average decline of 1.4% per year. The meta-analysis found no indication the decline is leveling off.
Their effects can be desired (hormonal contraception), a minor unwanted side effect (many antidepressants) or; a major public health problem (thalidomide). However, most studies of reproductive toxicity have focused on occupational or environmental exposure to chemicals and their effects on reproduction.
The semen in ejaculate contains sex cells called sperm. After intercourse, sperm travel to the egg through the female reproductive tract, typically causing fertilisation to occur in the fallopian tubes. Fertility testing for men involves semen testing and genetic testing, as other factors such as impotence are obvious.
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. Depending on the measurement method, just a few ...
Laboratory examination of seminal vesicle fluid requires a semen sample, e.g. for semen culture or semen analysis. Fructose levels provide a measure of seminal vesicle function and, if absent, bilateral agenesis or obstruction is suspected. [13] Imaging of the vesicles is provided by medical imaging; either by transrectal ultrasound, CT or MRI ...
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 ...
In studies that controlled for female age, comparisons between men under 30 and men over 50 found relative decreases in pregnancy rates between 23% and 38%. [4] Older men have lower semen parameters resulting in lower fertility potential. The effects of aging on semen quality are summarized below based on a study of 1,219 subjects: [5]
Women become less fertile as they get older. For women aged 35, about 94% who have regular unprotected sexual intercourse get pregnant after three years of trying. For women aged 38, however, only about 77%. The effect of age upon men's fertility is less clear. [91]