The average erect penis length has increased by 24% in 29 years and is now 13.93 cm. The result comes from a study by Dr. Michael Eisenberg, professor of urology at Stanford School of Medicine, which analyzed research by men’s health specialists funded between 1942 and 2021. However, the growth is viewed with concern by specialists in the medical field.
“The increase happened in a relatively short period of time. Any overall developmental change is of concern since our reproductive system is one of the most important parts of human biology. When we see such a rapid change, it means something powerful is happening to our bodies,” warns Michael, lead author of the study, in an interview with Stanford Medicine Magazine.
Michael Eisenberg, urologist (Photo: SMRU/Disclosure) The study, published on the 14th in the World Journal of Men’s Health, analyzed 75 studies that charted the length of the penis in 55,761 men and showed that the growth trend was noted worldwide, suggesting a global cause and not just regional factors. For the research team, environmental factors such as pollutants and exposure to chemical products or a sedentary lifestyle are responsible for the sudden change.
“Endocrine disruptors are abundant in our environment and in our diet. When we change the composition of our body, this also affects our hormonal environment. Exposure to chemical products has also been identified as a cause of earlier puberty in boys and girls, which can affect genital development,” explains the professor.
The factors have even caused other changes in men’s health, Michael recalls. Sperm count and testosterone levels in men are examples that prompted the specialist to examine whether environmental influences also promoted physical changes in this audience.
“Given the trends we’ve seen in other male reproductive health interventions, we thought there might be a decrease in penis length due to the same environmental pressures,” he says.
However, Michael’s theory was that the penis would have shrunk in recent years. In conducting the study, he found that the hypothesis was wrong. The average size of an erect penis used to be 10.5 cm.
“We conducted a metaanalysis looking at all the reports of penis length known to us. We look at flaccid, stretched and erect length and create a large database of measurements. What we found was very different from trends in other areas of fertility and men’s health.”
NEXT STEPS
Now the Stanford Medical School team plans to assess whether the environmental impacts are affecting other populations, such as growing children. The researchers want to analyze the national database of height and weight records maintained by paediatricians to ensure there are no significant changes. If so, says Michael, exposure to chemicals “could become an early indicator of changes in human development.”
“If there is detailed data on lifestyle factors or environmental pressures, we can also try to understand why this might be happening. Finally, I think it is important to ask whether similar changes take place in the female reproductive system.”