study of Stanford University School of Medicine shows that the average length of the erect penis increased by 24% in 29 years, a trend observed worldwide. Confronted with trends in male reproductive health data showing this Sperm quality and testosterone levels have declined over the past few decadesMichael Eisenberg, physician and professor of urology at the University of California, USA, decided to investigate whether the physical anatomy of the penis had also changed.
The study, published on Tuesday 14th in the scientific journal The World Journal of Men’s Health, compiled data from 75 studies conducted between 1942 and 2021 that reported the length of the penis of 55,761 men.
“The length of erect penis increased from an average of 12.1 centimeters to 15.2 centimeters over the past 29 years,” Eisenberg, one of the study’s authors, told Stanford University School Medicine’s Scope blog on the same day the study was published.
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For Eisenberg, the increase could be a further indicator that environmental pollution for example through environmental pollutants or an increasing sedentary lifestyle is causing reproductive changes.
Filipe Araújo/Estadão
The average penis length has increased by 24% in three decades, according to a Stanford Medicine study
Possible implications of the results for men’s health
According to the doctor, many studies have comprehensively analyzed changes in male reproductive health. “For example, sperm count and testosterone levels have been declining for a long time. There are also higher rates of male birth defects, such as hypospadias, where the urethral opening is not at the tip of the penis, and cryptorchidism, where the testicles don’t descend properly. Another measure we’ve seen in some male health surveys is penis length, and nobody’s looked at it systematically,” Eisenberg told Blog Scope.
Given the trends observed in other male reproductive health interventions, the doctor believed that there could be a decrease in penis length due to the same environmental stressors. “We conducted a metaanalysis looking at all the reports of penis length known to us. We look at flaccid, stretched and erect lengths and create a large database of measurements. What we found was very different from trends in other areas of fertility and male health.”
According to the researcher, the increase occurred in a relatively short period of time. “Any overall developmental change is worrying because our reproductive system is one of the most important parts of human biology,” Eisenberg said. “When we see such rapid changes, it means something powerful is happening to our bodies. We must try to confirm these results, and if they are confirmed, then we must determine the cause of these changes.”
The doctor also does not rule out that other factors may play a role. “Like exposure to chemicals like pesticides or hygiene products that interact with our endocrine systems,” he says.
According to Eisenberg, these are chemicals Endocrine disruptors are found in the environment and in food. “When we change our body composition, it also affects our hormonal environment. Exposure to chemicals has also been cited as a cause of earlier onset of puberty in both boys and girls, which can affect genital development,” he said in an interview with the blog.
The next step in the study will be to analyze other patient profiles, such as the pediatric population. “Just as we measure height and weight every year in the United States, this is another thing we can measure systematically because it can become an early indicator of changes in human development. If there is granular data on lifestyle factors or environmental pressures, we can try to understand why this is happening.”