The penis is a male organ with functions that include reproduction and urination. As with any body part, no two people have the same penis.

The penis has two main features. The body, or shaft, connects the penis to the abdomen. At the opposite end of the shaft is the glans, or head.

This article lists some common types of penises, categorized primarily by measurement, and provides some related information.
Length
Medical Illustration by Diego Sabogal

Penises come in different lengths when flaccid or erect.

Estimates about average penis length can vary. For example, one 2014 study looked at the penis size of United States males. It found that the average erect length was around 5.6 inches.

However, another article suggests there are issues with many penis length studies, including the fact that participants self-report measurements.

These studies use self-reported data and are therefore subject to bias, which likely fuels the widespread belief that the average penis size is closer to 6 inches. In reality, the average is likely to be lower.
Girth

Penises also have different girths or circumferences.

A 2014 study into the penis size of U.S. males found that the average erect girth was around 4.8 inches.

However, as with penis length, a person should note that many penis girth studies use self-reported measurements, which are known to be fairly unreliable.
Curvature

Some penises are completely straight when erect. However, many have a bend or curvature. There are three main types of curved penis. These include penises that:

curve upwards from its base
curve downwards from its base
curve to the left or right

Additionally, some people may have multiple kinds of curvature. For instance, some penises may curve to the left and upwards.

Penile curvatures are common and typically benign. They are rarely painful and do not usually make penetrative sex more difficult.

However, abnormal penile curvature can sometimes be a symptom of Peyronie’s disease. One review lists the following as possible symptoms:

a thickened area, or plaque, in the penile shaft
curvature of the penis during erection
pain in the penis
erectile dysfunction

Scientists are not sure what causes Peyronie’s disease.

One common explanation is that the condition results from mild, recurring trauma to the penis. This can occur during intercourse or masturbation.

Peyronie’s disease can also be due to a rupture in the penis, known as a penile fracture. Genetic factors may also contribute to the development of this condition.

Anybody who suspects they may have Peyronie’s disease should seek medical advice. Sometimes, people with the condition who experience no other issues, such as pain, could still use their penis for sexual activity without needing medical treatment.

In some cases, doctors may recommend surgery to remove the plaque or reduce the curvature in the penis.

enile melanosis is a rare condition that causes discolored areas of skin on the head and shaft of the penis.

These patches are dark brown and may be slightly or significantly darker than the surrounding skin on the penis.

Penile melanosis does not cause any other symptoms. The condition is not infectious or contagious, and there is no way to pass it on to other people. However, the exact cause is still unknown.

Penile melanosis is generally harmless and does not require treatment. Some people may choose to have cosmetic procedures to remove the spots, though.

In this article, learn more about penile melanosis, including the causes, associated conditions, and treatment options.
What is penile melanosis?
Doctors do not know what causes penile melanosis.

Penile melanosis refers to patches of brown or dark brown skin on the penis. These spots are typically large and flat, with each one appearing alone.

Melanin is one of the main pigments in the skin, and people with more melanin have a darker skin tone. Melanosis refers to a buildup of melanin.

Penile melanosis may also involve other pigment compounds in the skin, such as:

hemosiderin
lipofuscin
ferrous sulfate

As these pigment compounds build up, they can cause a noticeable change in the skin’s color. This hyperpigmentation appears in patches on the penis, rather than affecting the entire penis.
Causes

Doctors are not sure why some people develop penile melanosis. It is simply a buildup of pigment cells within the skin, which can occur in other locations as well.

However, possible risk factors that may increase a person’s chances of developing penile melanosis include:

Age: While penile melanosis can affect people of any age, it mostly appears between the ages of 15 and 72 years.
Genetics: There may be a genetic component to penile melanosis.
Injuries: Previous injury to the penis may play a role, as the formation of scar tissue can lead to hyperpigmentation.
Certain skin treatments: Treatment with certain drugs, such as anthralin or PUVA therapy, may increase the risk of penile melanosis.

Penile melanosis and lichen sclerosus

Penile melanosis may also have a link to another uncommon skin condition called lichen sclerosus.

Lichen sclerosus causes thin, pale patches of skin, usually in the genitals or hands. A 2017 case study of an older man found an association between the penile melanosis and lichen sclerosus on his penis.

However, this does not mean that one of these conditions causes the other. It simply suggests that there may be a link between them.
Penile melanosis and cancer

Some people may worry that discolorations such as these will lead to melanoma, a form of skin cancer. Penile melanoma is very rare.

Penile melanoma may cause darker spots of skin similar to those of penile melanosis, but typically just on the head of the penis. These may grow, change color, and bleed.

WHO And UNAIDS Recommend Male Circumcision As A Step Towards HIV Prevention

n response to the urgent need to reduce the number of new HIV infections globally, WHO and the UNAIDS Secretariat convened an international expert consultation to determine whether male circumcision should be recommended for the prevention of HIV infection.

Based on the evidence presented, which was considered to be compelling, experts attending the consultation recommended that male circumcision now be recognized as an additional important intervention to reduce the risk of heterosexually acquired HIV infection in men. The international consultation, which was held 6-8 March 2007 in Montreux, Switzerland, was attended by participants representing a wide range of stakeholders, including governments, civil society, researchers, human rights and women's health advocates, young people, funding agencies and implementing partners.

"The recommendations represent a significant step forward in HIV prevention," said Dr Kevin De Cock, Director, HIV/AIDS Department in WHO. "Countries with high rates of heterosexual HIV infection and low rates of male circumcision now have an additional intervention which can reduce the risk of HIV infection in heterosexual men. Scaling up male circumcision in such countries will result in immediate benefit to individuals. However, it will be a number of years before we can expect to see an impact on the epidemic from such investment."

There is now strong evidence from three randomized controlled trials undertaken in Kisumu, Kenya; Rakai District, Uganda (funded by the US National Institutes of Health); and Orange Farm, South Africa (funded by the French National Agency for Research on AIDS) that male circumcision reduces the risk of heterosexually acquired HIV infection in men by approximately 60%. This evidence supports the findings of numerous observational studies that have also suggested that the geographical correlation long described between lower HIV prevalence and high rates of male circumcision in some countries in Africa, and more recently elsewhere, is, at least in part, a causal association. Currently, 665 million men, or 30 % of men worldwide, are estimated to be circumcised.

Male circumcision should be part of a comprehensive HIV prevention package
Male circumcision should always be considered as part of a comprehensive HIV prevention package, which includes
the provision of HIV testing and counselling services;
treatment for sexually transmitted infections;
the promotion of safer sex practices; and
the provision of male and female condoms and promotion of their correct and consistent use.

Counselling of men and their sexual partners is necessary to prevent them from developing a false sense of security and engaging in high-risk behaviours that could undermine the partial protection provided by male circumcision. Furthermore, male circumcision service provision was seen as a major opportunity to address the frequently neglected sexual health needs of men.