HealthInfo Waitaha Canterbury
A boy's testicles are two small egg-shaped organs that sit inside his scrotum.
The spermatic cord is like a long and flexible tube that goes from each testicle to inside the boy's tummy (abdomen). It contains the blood vessels that take blood to and from the testicle, and the vas deferens, which takes sperm from a boy's testicles to his penis once he has reached puberty.
A boy can usually feel the spermatic cord through the skin of his scrotum, just above his testicle. It feels like a thick piece of string.
A structure called the epididymis, which is where sperm is stored, is at the top and back of each testicle.
The testicles are both about the same size. But it's normal for one to be slightly bigger than the other and for one to hang a bit lower than the other. They should feel smooth and firm (not hard) and without any lumps or bumps.
When a boy's around 11 to 12 years old, their testicles start growing bigger. This continues until they reach early adulthood.
In some pēpi (babies), one or both of the testicles stay up in the tummy and do not come down into the scrotum. This is known as undescended testicles. It's usually found at the baby's 6 weeks check and may need surgery to correct it.
Several conditions can cause sudden pain in a boy's scrotum. If this happens, it's a medical emergency.
Boys also sometimes get lumps in their scrotum. Usually these are harmless lumps like hydroceles. Less often a lump can be caused by an inguinal hernia.
Written by HealthInfo clinical advisers. Last reviewed August 2022.
Review key: HITSP-309438