Many patients are concerned about the question, “Am I circumcised”, so how can we simply determine this? Here I give you a simple introduction, hope to help you! The skin of the penis is folded into a double layer at the head of the penis, called the foreskin, before the age of 7, the foreskin is long and can completely wrap the head of the penis and the urethral opening. With the development of puberty, the volume of the penis increases and lengthens, and the foreskin retreats backwards to reveal the head of the penis in adulthood. However, about 30% of adult foreskin still completely cover the head of the penis. Circumcision is a condition in which the skin of the penis wraps around the glans and the glans cannot be fully exposed when a man reaches adulthood. This can be divided into true circumcision and pseudo-circumcision. True circumcision is the penis is erect after the glans can not be fully exposed; pseudo-circumcision is usually the glans can not be fully exposed, but after the penis is erect the glans can be fully exposed. The circumcision refers to the narrow opening of the foreskin that completely wraps the glans, the glans cannot be exposed at any time, and the foreskin is difficult to be turned up. To determine whether it is circumcision or prepuce, you can determine through self-examination by applying soap to the penis, lubricating the foreskin inside and outside, fixing the penis with the left hand, pushing the foreskin backward with the right hand and turning it over, if the foreskin can be turned up smoothly, it is circumcised; if the opening of the foreskin is too small to be turned up, it is circumcised.