What is a penis?

Let us introduce you to the reproductive system of people with male anatomies — otherwise known as a penis! And testes (commonly called ‘balls’).

Check out this video for a quick introduction to the penis. 

For those with a male reproductive system, their reproductive organs can be found both inside and outside the pelvis. These organs include:


The testicles (or testes) are two organs that are oval shaped and usually grow to be about 5 cm in length and about 3 cm wide. This is where millions of sperm cells are produced and stored. It is completely normal for one testicle to be a bit bigger than the other. 

The testicles also produce the male sex hormone testosterone. This is the hormone responsible for the majority of changes people assigned male at birth experience during puberty such as: the deepening of the voice; rapid muscle growth; as well as increased body and facial hair; and the production of sperm.

The Duct System

Alongside the testicles is what’s known as the ‘epididymis’ and the ‘vas deferens’. These are muscular tubes which transport the sperm-containing fluid (semen) from the testicles towards the penis.

The scrotum

The scrotum is a pouch or sac of skin that contains the testicles and the duct system. It has one job: keep the sperm at the perfect temperature! In fact, when it’s cold, it will shrivel up to keep the sperm warm. When it’s hot, the scrotum relaxes to cool its cargo!

A diagram of the male reproductive system.
The accessory glands

These glands include the seminal vesicles and the prostate gland. They provide fluids that lubricate the system and help keep the sperm healthy.


This is the channel that carries the semen outside the body when people with penises ejaculate. The urethra also carries urine.

The Penis

This is actually made up of two parts; the muscular shaft, the long section of the penis and the glans, which is the tip or head of the penis. The shaft is the part of the penis which hardens during an erection.


This is a little ‘hood’ of skin that covers the glans or tip of the penis. In some instances people with penises are circumcised, meaning that the hood of skin is cut away by either a doctor or a religious leader. Whether someone is circumcised or not has no effect on the function of their penis! Check out this clip for some more info if you are interested to know a little more about circumcision.

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We acknowledge the Traditional Custodians of the lands on which Rosie has been created, the Wurundjeri Woiwurrung people of the Kulin Nation, and pay our respects to elders past and present. Always was, always will be Aboriginal land.

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