Scientists reveal men who were obese as children may be less well endowed – and the bizarre reason why
Men who are obese as children are at higher risk of having shorter penises as adults, research has suggested.
Vietnamese scientists, who assessed the link in almost 300 men, discovered their body-mass-index (BMI) score as adults had no impact on size.
A score of 18.5 to 25 is healthy, 25 to 29 is overweight, and 30 or above counts as obese—the point at which the risk of serious illness soars.
Instead, they found those who were classed as obese as children suffered shorter ‘penile growth’ and were less endowed as adults.
Scientists could not say exactly why this was the case.
But they suggested it may be because obesity is associated with a decline in the male sex hormone testosterone during puberty, and testosterone is important for penile development.
Writing in the Journal of Sexual Medicine, researchers said: ‘Childhood obesity is associated with penile growth, while adulthood obesity relates to the appearance of the penis rather than the actual size.
‘Thus, there is a need for early interventions to mitigate the potentially long-term effects of childhood obesity on penile development.’
Vietnamese scientists found that men who were classed as obese as children suffered shorter ‘penile growth’ and were less endowed as adults (stock image)
In the study, researchers assessed 290 men who visited Hanoi Medical University Hospital for reproductive health checkups between 2023 and 2024.
They measured participants’ height, waist and hip circumference, hand circumference as well as penis size — including including length and circumference, in flaccid, stretched, and erect states.
Scientists also asked study volunteers to estimate their BMI at 10-years-old, before puberty starts for most children.
Research suggests that the average erect penis length is around 13 to 14 centimeters, with variation among countries.
The scientists found that on average study participants had a flaccid length of 8.9cm and 14.4cm when stretched.
They also discovered that obese men had slightly wider diameters than overweight men, but not compared to those classed as a healthy weight.
‘Prepubertal obesity was associated with shorter stretched and flaccid lengths in adulthood,’ they said.
‘Childhood obesity may have a relationship with penile growth, whereas adulthood obesity primarily affects penile appearance rather than actual size.’
Previous research has suggested that obesity as an adult can be a culprit of penile shrinkage.
Losing 10kg (1st 8lb) or so could even give the penis an extra centimetre in length, experts say.
This is because fat contains enzymes that convert testosterone to estrogen — a female sex hormone.
Without enough testosterone, the penis may shrink or shrivel up.
In some cases where the penis appears smaller, it might not actually be shrinking.
Lower abdominal fat can pull the organ inward or envelope the shaft, which makes it look smaller.
Therefore, losing weight can help pull the penis out more and make it seem larger.
More than a quarter of adults and a fifth of Year Six pupils in England are now classed as obese.
A sobering report last year warned that Britain’s spiralling weight problem has fuelled a 39 per cent rise in type 2 diabetes among under-40s, with around 168,000 young adults now living with the disease.
Excess weight has also been linked to at least 13 types of cancer and is the second-biggest preventable cause of the disease in the UK, according to Cancer Research UK.
