Size and other body parts
One study, Siminoski and Bain (1988), found a weak correlation between the size of the stretched penis and foot size and height; however, it was too weak to be used as a practical estimator. Another investigation, Shah and Christopher (2002), which cited Siminoski and Bain (1988), failed to find any evidence for a link between shoe size and stretched penis size, stating "the supposed association of penile length and shoe size has no scientific basis".A study by Ikegaya et al. (2021) concluded that nose size was highly related to stretched penile length in Japanese male cadavers.There may be a link between the malformation of the genitalia and the human limbs. The development of the penis in an embryo is controlled by some of the same Hox genes (in particular HOXA13 and HOXD13) as those that control the development of the limbs. Mutations of some Hox genes that control the growth of limbs cause malformed genitalia (hand-foot-genital syndrome). Size and race
Alleged differences in races have led to the creation of sexual myths.
They found a few statistically significant Spearmans correlations: between flaccid length and height of 0.208, −0.140 with weight, and −0.238 with BMI, flaccid circumference and height 0.156, stretched length and height 0.221, weight −0.136, BMI −0.169. They also reported a few non-significant correlations. Erect
Scientific studies have been performed on the erect length of the adult penis. Studies that have relied on self-measurement, including those from Internet surveys, consistently reported a higher average length than those that used medical or scientific methods to obtain measurements.The following staff-measured studies are composed of different subgroups of the human population (in other words, specific age range or race; selection of those with sexual medical concerns or self-selection) that could cause a sample bias. In a study of 80 healthy males published in the September 1996 Journal of Urology an average erect penis length of 12.9 cm (5.1 in) was measured. The purpose of the study was to "provide guidelines of penile length and circumference to assist in counseling patients considering penile augmentation." Erection was pharmacologically induced in 80 physically normal American men (varying ethnicity, average age 54). It was concluded: "Neither patient age nor size of the flaccid penis accurately predicted erectile length." A study published in the December 2000 International Journal of Impotence Research found that average erect penis length in 50 Jewish Caucasian males was 13.6 cm (5.4 in) (measured by staff). The study intended "to identify clinical and engineering parameters of the flaccid penis for prediction of penile size during erection."