Fine-touch pressure thresholds in the adult penis https://www.cirp.org/library/anatomy/sorrells_2007/
CONCLUSIONS 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.

You dont need studies to prove this its intuitive. all that research just to say removing important stuff = bad