A condition in which veins become larger inside the loose pouch of skin that holds the testicles, called the scrotum.

Most often, varicoceles form during puberty and develop over time. They may cause a testicle to develop poorly or make less sperm. They're also linked with a higher risk of infertility.

A varicocele often causes no symptoms. But a person might have aching pain, a growth above the testicle that feels like a "bag of worms," different-sized testicles, or trouble getting a partner pregnant.

Often, a varicocele doesn't need treatment. If it causes pain, an athletic supporter or pain medicine sold over the counter might help. Surgery might be recommended if a varicocele seems to cause health issues such as infertility.