About three-quarters of men in the United States are circumcised, slightly down from a peak of 80% fifty years ago. Rates are highest among white men, while only two-thirds of African-Americans and half of Latinos are circumcised. In no other country in the world are men circumcised at birth so routinely, unless for religious reasons. Circumcision was once thought to prevent boys from masturbating and becoming morons. Though that Victorian myth has been debunked, three-quarters of American mothers still consider a circumcised penis more visually and sexually appealing and more hygienic and request the procedure for their newborn boys.
The foreskin of uncircumcised men cloaks the head (or glans) of the penis in the flaccid state, often covering it completely like a drawn purse, except when it is manually retracted. The foreskin is like a cuff, with skin on the outer surface and a pinker mucous membrane on the inside. This inner surface is similar to the mucous membranes of the lips, vagina, and anus. When the penis is erect, the foreskin unrolls over the lengthening shaft, and the penis becomes virtually indistinguishable from a circumcised penis, except that the unrolled portion may be moister and pinker.
Medical journals continue to debate whether circumcision (or “male genital mutilation,” as some refer to the practice) affects sexual functioning in men. The foreskin contains specialized sensory nerve cells that detect vibration and motion, and glands which secrete lubricating fluids during sexual arousal, and these would be lost during circumcision. The head of the penis is probably more sensitive in uncircumcised men, because the mucosal surface turns into normal skin if the foreskin is removed. But it has been difficult to scientifically prove any difference in sensitivity, or whether greater sensitivity is good (easier to arouse) or bad (more tender) for uncircumcised men. Also, men with intact foreskins can accumulate a greasy white substance, called smegma, though this is rarely noticeable and easily cleaned. A number of studies have shown that men who are circumcised as adults are generally happy with the results, and circumcised men may have more oral sex, more anal sex, more frequent masturbation, and less sexual dysfunction.
There is no objective medical or aesthetic reason for prefering a cut or uncut penis. For most men, the choice was made for them by their parents. Otherwise, it comes down to personal preferences one might have in a partner, if one cares at all.