The study, published in The Journal of Sexual Medicine, looked at a group of 40 men, half of them circumcised. Using sensory testing, the men were monitored at two points on the penis and the forearm while viewing erotic films. Thermal imaging was used to measure sexual arousal.
I think one can criticize this study on the relative coarseness of measure, after all, registering qualia is not a trivial task. Nevertheless, do note that in my previous comment on circumcision I did suggest that “pleasure” might be renormalized by the brain. Remember how good McDonald’s tasted when you are 8 years old?