Main article: Human penis size
While results vary across studies, the consensus is that the average erect human penis is approximately 12.9-15 cm (5.1-5.9 in) in length with a 95% confidence interval of (10.7 cm, 19.1 cm) or (4.23 in, 7.53 in). The typical girth or circumference is approximately 12.3 cm (4.84 in) when fully erect. The average penis size is slightly larger than the median size (i.e. most penises are below average in size).
A research project, summarizing dozens of published studies conducted by physicians of different nationalities, shows that worldwide, erect-penis size averages vary between 9.6 and 16 cm (3.8 and 6.3 in). It has been suggested that this difference is caused not only by genetics, but also by environmental factors such as culture, diet, chemical/pollution exposure,etc. Endocrine disruption resulting from chemical exposure has been linked to genital deformation in both sexes (among many other problems).
The longest officially documented human penis was a find by Doctor Robert L. Dickinson. It was 34.3 cm (13.5 in) long and 15.9 cm (6.26 in) around.
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