Overweight and obese boys have 50% smaller testicles, study finds

Overweight or obese boys have smaller testicles than their normal-sized peers, a study found.

Scientists in Italy who conducted the study warned that the extra weight also leads to a higher risk of lower sperm counts and infertility in adulthood.

In the study, overweight and obese children between the ages of nine and 14 — when they go through puberty — had testicles that were about 50 percent smaller than normal-sized ones.

Among young people with hyperinsulinaemia, high insulin levels and a precursor to type 2 diabetes, their testicles were up to half the size of their peers.

Being overweight or obese can limit testicular growth, scientists warned, because it can disrupt hormones and lead to heat stress on the scrotum.

Children’s weight status was calculated using body mass index, which divides weight by height. A higher score puts a child in the overweight or obese range.

Scientists have been sounding the alarm for years about declining male sperm counts, with some now warning that “human survival is at risk.”

In 1973, the average sperm count was about 104 million per milliliter, studies show.

But by 2019, this had dropped to just 49 million – a halving in less than 50 years.

Expanding waistlines, sedentary lifestyles, and even exposure to chemicals like pesticides are all to blame for the shift.

Dr. Rossella Cannarella, a fertility expert at the University of Catania in Sicily, Italy, who conducted the study, warned obese boys have a higher risk of infertility in adulthood.

She said: ‘Those with overweight or obesity, hyperinsulinemia or insulin resistance showed lower testicular volume than their healthy peers

“We speculate that more careful control of body weight in childhood could be a prevention strategy for preserving testicular function later in life.”

The press release adds that the paper “indicates that overweight boys tend to have lower testicular volume, putting them at risk for infertility in adulthood.”

For the study, scientists looked at data on the testicular volume of children who were referred to the university’s Pediatric Endocrinology Unit for weight management.

They were compared to a group of healthy weight children who also had their testicle size measured.

The study looked at 268 children, 206 of whom were overweight, obese or severely obese, while the rest were normal weight.

Children were split into three groups, from children under nine – pre-puberty – nine to 14 years old – during puberty – and 14 to 16 years old – after puberty.

The results showed that obese or overweight children aged 9 to 14 years had significantly smaller testicles than their normal-sized peers.

Those 14 to 16 years old and with hyperinsulinemia had testicles half the size of their healthy peers.

Adolescence is critical for the development of testicles as they go through great growth to produce sperm.

But previous research has shown that being overweight or obese can disrupt this because fat cells can disrupt the hormone balance in the body.

The excess weight can also lead to heat stress on the testicles or being kept above the 95 to 96F needed, which can harm development.

In the study, the scientists suggested that overweight or obese children likely had lower levels of the hormone inhibin B, which is made by the testicles and is essential for stimulating the growth of sperm-producing cells.

They also said that hyperinsulinemia could inhibit the growth of Sertoli cells in the testes, which are also essential for sperm production.

Dr. Cannarella added, “In this study, we found that being overweight or obese was associated with lower peri-pubertal testicular volume.”

The research has been published in the European journal of endocrinology.