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.

Daily urinary creatinine excretion and creatinine coefficient of eighty-four healthy medical students have been studied for three consecutive days. Daily creatinine excretion has been observed to be higher in the male subjects compared to the female counterparts. Creatinine excretion has been observed to be dependent on body weight of the subjects. The variability from subject to subject was higher than observed by most other workers. Day to day consistency within the same subject was rather low. Creatinine coefficient was computed per kg of body weight as well as per kg of lean body weight. In both the cases, it has been found to be higher in the males than in the females. Though an important factor, yet body weight of a subject alone could not explain satisfactorily wide variability of creatinine excretion in the present study. The possible influencing factors have been discussed along with clinical implications.

S P Singh

Papers

Some observations on human semen analysis.

A study of urinary creatinine and creatinine coefficient in healthy young adults.