Researchers at the University of Catania in Italy reported that overweight or obese men have noticeably smaller testicles compared to peers without weight concerns. The study also identified an elevated risk of low sperm counts and infertility later in life. The findings were published in the European Journal of Endocrinology.
The study population included 268 boys aged 9 to 16, with 200 of them categorized as overweight or obese. In that overweight group, the testicles were about 50% smaller on average, and adolescents with higher insulin levels—an early marker linked to type 2 diabetes—had testicles roughly half the size of their peers who did not show insulin elevation.
Researchers suggest that excess body weight disrupts hormonal balance and can create heat stress in the scrotal area. This combination may contribute to reduced testicular size and, over time, a lower active sperm count, potentially increasing the likelihood of infertility in adulthood.
In related clinical observations, former urologist Dmitriev described a condition in which testicles may appear to separate or descend abnormally toward the thigh area, underscoring the importance of medical evaluation when significant changes are noticed.