Scientists from Stanford University have found that penile length has increased by 24% during an erection over the past 29 years. The results are published in: World Men’s Magazine.
The researchers examined 20 studies involving 18,000 men conducted from 1992 to 2021. It turned out that the average length of the erect penis increased from 12.2 to 15.2 cm. In all studies, the measurements were made by doctors, and the erected length was estimated from the length of the stretched organ.
Recent research has shown that average sperm count and testosterone levels in men have dropped over the past few decades, so scientists expected to find a reduction in average penile length.
The authors of the study believe that environmental factors may play a role in increasing the average length of the penis. Some previous research has shown that some common substances are associated with precocious puberty in boys and girls, which can affect the development of the genitals.