During the 1970s, physicians Raymond Bunge and C. M. Kinloch Nelson investigated the possible changes in sperm of the general male population. After looking at the sperm samples from 386 fertile men, they found out that the participants had less semen volume than men in the studies prior. They also show a higher amount of abnormal sperm and a lower concentration of sperm in the semen. Bunge and Nelson predicted that environmental factors affect the population at large.

Since the publication of this research, a number of studies have been conducted to compare the sperm quality of men. Some studies measured sperm count, while some measured sperm concentration. From these studies, some researchers observed a decrease in sperm count, while others saw no change. These inconsistencies are even more complicated by the difference in sperm count by factors such as age, season, frequency of ejaculation, and geographical location.

Challenges in Measuring Sperm Count

Sperm count refers to sperm concentration, measured by the number of sperm in one milliliter of semen. In a standard sperm test, a man undergoes semen analysis regarding sperm concentration, sperm motility, and sperm morphology. At least 20 million sperm cells per milliliter are needed for a sperm concentration to be expected.

Sperm counts seem challenging to be compared across different study populations. Even if large-scale studies suggest a global decline in sperm count, few researchers are skeptical that the findings might be far from the truth. 

One of the challenges in getting accurate sperm count is that sperms move, and not all studies immobilize sperm before counting them. Aside from it, the semen is not always well mixed, so that the numbers can differ within a given sample.

An accurate way to determine sperm count is using an automated tool known as cytometry. However, this method was not available when the older studies were performed. If old and new studies are compared, the ones that use the latest methods must be excluded in favor of the simpler strategies. Another issue that needs to be addressed is past studies' failure to determine whether sperm counts change in a given population.

READ ALSO: Semen Quality May Determine Future Health Condition Amongst Adult Men


Effect of Sperm Count on Male Fertility

Several factors can cause infertility in both men and women. Urology Care Foundation says one-third of infertility cases are attributed to the man. Most experts link this to his sperm production or sperm delivery.

The different results of the studies on sperm count spark debate among male fertility experts. After all, sperm count is not a precise measure of fertility. Although higher sperm counts are linked with a high success rate of getting pregnant, it is still possible to conceive with lower counts. If a man's sperm count is not zero, he can get his partner pregnant with time.

Male fertility depends on a man's ability to make normal sperm and deliver them to the woman's body. Fertilizing an egg cell by the sperm cell will only work if the genes, hormone level, and environmental conditions are right.

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