Study published in BJUI (British Journal of Urology International), Volume 99, Issue 4, Pages 864-869 (March 2007). This is the Sorrells study. The Sorrels study is remarkable because it used objective measurements to determine fine-touch sensitivity of various parts of the intact penis and the circumcumcised penis, showing that circumcision removes the most sensitive parts of the penis.

Watch a YouTube video of Dr. Sorrells discussing the study and his results.

Adult male volunteers with no history of penile pathology or diabetes were evaluated with a Semmes-Weinstein monofilament touch-test to map the fine-touch pressure thresholds of the penis. Circumcised and uncircumcised men were compared using mixed models for repeated data, controlling for age, type of underwear worn, time since last ejaculation, ethnicity, country of birth, and level of education.

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The type of nerve endings in the penis vary with location. The glans penis primarily has free nerve endings that can sense deep pressure and pain. The transitional area from the external to the internal surface of the prepuce, or ‘ridged band’, has a pleated appearance that is continuous with the frenulum and has a high density of fine-touch neuroreceptors, such as Meissner’s corpuscles

The study concluded that the "glans of the circumcised penis is less sensitive to fine touch than the glans of the uncircumcised penis. The transitional region from the external to the internal prepuce is the most sensitive region of the uncircumcised penis and more sensitive than the most sensitive region of the circumcised penis. Circumcision ablates the most sensitive parts of the penis."

In conclusion, circumcision removes the most sensitive parts of the penis and decreases the fine-touch pressure sensitivity of glans penis. The most sensitive regions in the uncircumcised penis are those parts ablated by circumcision. When compared to the most sensitive area of the circumcised penis, several locations on the uncircumcised penis (the rim of the preputial orifice, dorsal and ventral, the frenulum near the ridged band, and the frenulum at the muco-cutaneous junction) that are missing from the circumcised penis were significantly more sensitive.