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A comprehensive review of previously conducted studies did not find that overweight males have more difficulty fathering a child. But a new study found that heavy men are more likely to have low sperm counts or no production of sperm.
According to this study headed by Dr. Jorge Chavarro of the Harvard School of Public Health, men with lower sperm counts will have more difficulty with conception than men with higher sperm counts. It’s not just the numbers that matter, it’s the condition of the sperm. How well they move, what shape they are, and the quality of the DNA they carry all are taken into consideration when fertility is in question. Previous studies have shown that all of these qualities can be affected by weight.

According to scientists, it takes just one sperm to fertilize an egg and in turn achieve pregnancy. There are millions of sperm ejaculated and very few will reach the egg. The average ejaculate contains close to 100 million sperm. The World Health Organization tells us that fewer than 20 million of these swimming male sprouts per milliliter of semen are not enough to achieve conception.

French Scientists Find Fat Affects Fertility

These French scientists compiled data from fourteen different research studies that compared sperm counts in samples of ejaculate from those of normal weight and compared it to those men who were overweight or obese. They also included data from their own fertility center with the research. Around one-fourth of the combined 10,000 male subjects had a low sperm count and in another analysis, approximately 250 out of 7,000 men had no sperm in their ejaculate at all.

With the data collected, the researchers from the Ambroise Pare Hospital in Boulogne-Billancourt compared the findings of normal weight men to the overweight ones. The chubby men classified as “overweight” were 11 percent more likely to have a low sperm count and a whopping 40 percent change of having no sperm at all in the ejaculate. What’s more, the men classified as “obese” were 42 percent more likely to have a low sperm count and around an 80 percent chance of having sperm-free ejaculate.

The Thick Theories

A number of different theories were proposed by the physician researchers. First of all it was suggested that the male hormone levels were altered and more estrogen was produced from the fat tissue. This was thought to adversely affect the sperm counts of the overweight and obese individuals. Also, the scientists proposed that more fat in the stomach and hip areas could make the scrotum too hot, thus killing the once viable sperm.

The researchers warned that these results do not prove that chubby men will definitely have fertility trouble and it is possible that their weight isn’t to blame. It was hypothesized that some men have underlying health conditions that will cause them to gain weight and that condition affects the sperm. It is not a definite fact that losing weight will boost the sperm production of overweight men, the researchers concluded, in fact some case reports have suggested that weight-loss surgery may have a negative effect on sperm.

These findings were published in the Archives of Internal Medicine.

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  • Photo courtesy of 57378663@N06 on Flickr: