OBJECTIVE--To investigate whether semen quality has changed during the past 50 years. DESIGN--Review of publications on semen quality in men without a history of infertility selected by means of Cumulated Index Medicus and Current List (1930-1965) and MEDLINE Silver Platter database (1966-August 1991). SUBJECTS--14,947 men included in a total of 61 papers published between 1938 and 1991. MAIN OUTCOME MEASURES--Mean sperm density and mean seminal volume. RESULTS--Linear regression of data weighted by number of men in each study showed a significant decrease in mean sperm count from 113 x 10(6)/ml in 1940 to 66 x 10(6)/ml in 1990 (p < 0.0001) and in seminal volume from 3.40 ml to 2.75 ml (p = 0.027), indicating an even more pronounced decrease in sperm production than expressed by the decline in sperm density. CONCLUSIONS--There has been a genuine decline in semen quality over the past 50 years. As male fertility is to some extent correlated with sperm count the results may reflect an overall reduction in male fertility. The biological significance of these changes is emphasised by a concomitant increase in the incidence of genitourinary abnormalities such as testicular cancer and possibly also cryptorchidism and hypospadias, suggesting a growing impact of factors with serious effects on male gonadal function.

https://www.bmj.com/content/bmj/305/6854/609.full.pdf

Evidence for decreasing quality of semen during past 50 years.

/pdf/evidence-for-decreasing-quality-of-semen-during-past-50-vlioqbfqzo.pdf

Evidence for Decreasing Quality of Semen During Past 50 Years

A fluid medium was developed to simulate the salient physical and chemical properties of human semen. The composition of the medium was based upon an extensive review of the literature on constituents of human semen. In choosing the ingredients for this medium, the goal was to emphasize properties that influence interactions of human semen with topical contraceptive, prophylactic, or therapeutic products. Among these properties, pH and buffering capacity, osmolarity, ionic strength, and rheological properties play dominant roles in the physico-chemical processes that govern drug release kinetics and delivery vehicle distribution.

https://onlinelibrary.wiley.com/doi/pdf/10.2164/jandrol.04104

A review of the physical and chemical properties of human semen and the formulation of a semen simulant.

Recent reports have suggested that the incidence of genitourinary abnormalities in human males has increased during the past 50 years, including congenital abnormalities such as cryptorchidism and ...

Evidence for increasing incidence of abnormalities of the human testis: a review.

Sperm counts in Asian men: Reviewing the trend of past 50 years

Semen analysis of 66 unmarried medical students in the age group of 17-21 years was carried out. A higher liquefaction time pH, motility, lower sperm count and abnormal forms were observed compared to reported values. Liquefaction time, pH and sperm count was found significantly different in non-vegetarians and vegetarians, perhaps due to difference in their dietary proteins.

Some observations on human semen analysis.

183 students of 17-22 years age group were studied in respect of fluid intake, urine output and urine titratable acidity under normal conditions for two consecutive days. The study was performed in early winter in eastern part of U.P. Male students were observed to have higher fluid intake and urine output as compared to female. Average fluid intake and urinary output in male students were observed to be 2860 S.D. +/- 780 ml and 1860 S.D. +/- 880 ml respectively while corresponding readings for female students were 1980 S.D. +/- 390 ml and 1550 S.D. +/- 840 ml. Titratable acidity was observed to be high with a mean of 47.46 meg S.D. +/- 16.2 meq as compared to commonly accepted average range of 25-35 meq. Nonvegetarian subjects were found to have significnatly higher titratable acidity. Fluid intake and urine output did not have any significant effect on titratable acidity of urine in both the sexes. Need for further studies on this subject has been stressed.

D N Pandey

Papers

Some observations on human semen analysis.

Study of the intake of fluid, output and titratable acidity of urine in medical students.