Penis size remains, for many men, a sensitive subject. What if certain differences observed in adulthood found their origin… in childhood? This is the question asked by Vietnamese researchers from Hanoi Medical University Hospital.
An unexpected link between weight and genital development
Between June 2023 and July 2024, they conducted a study on 290 adult men who came for a reproductive health check-up. Their objective: to determine whether being overweight before puberty could influence long-term penis growth.
The scientists measured the participants’ height, weight, waist and hip circumferences, and penis length at three different times: flaccid, stretched, and erect.
Each volunteer also estimated their body mass index (BMI) at age 10, just before puberty, a key period of hormonal development.
Being overweight before puberty slows down penis growth
The findings, published in the Journal of Sexual Medicineare unequivocal. In the sample, the average penis length in the flaccid state was 8.9 cm, and 14.4 cm when stretched.
The authors noted that men who suffered from childhood obesity had shorter flaccid and stretched penis length than those who had been of normal weight before puberty.
In contrast, adult BMI showed no correlation with penis size. According to researchers, adult obesity can make the penis appear smaller, due to fatty tissue in the pubic area, but this does not affect its actual growth.
“Childhood obesity is associated with penis growth, while adult obesity mainly influences its appearance. Hence the importance of early interventions to reduce the long-term effects of childhood obesity” they write.
Why does early obesity have this effect?
Everything would come down to puberty, when testosterone – the main male sex hormone – stimulates genital growth. Obesity tends to lower testosterone levels: body fat contains enzymes called aromatases, which transform testosterone into estrogens, the female hormones. This hormonal imbalance could slow down penis development at the crucial time of sexual maturation.
“Relative testosterone deficiency during puberty can have lasting effects on male sexual morphology. specify the researchers.
Preventing childhood obesity from an early age
This study serves as a reminder that childhood obesity is not limited to cardiovascular or metabolic risks. It can also have lasting hormonal and anatomical consequences. Encouraging a balanced diet, regular physical activity as well as early medical monitoring remains essential, the authors conclude.