Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein.

Spermatozoa (sperm)

A group of sperm, with detail of a single sperm

Spermatozoa (sperm) are the male sex cells that carry a man's genetic material. They are so tiny that they can't be seen without a microscope. In a healthy man, one ejaculation usually contains between 40 million and 600 million sperm.

Sperm have an oval head, a short middle, and a long tail. They move by whipping their tails. A sperm fertilizes a woman's egg (ovum) by breaking through the membrane that surrounds the egg.

Sperm develop in a man's testicles. They are added to semen before a man ejaculates.

Current as of: August 21, 2019

Author: Healthwise Staff
E. Gregory Thompson, MD - Internal Medicine
Adam Husney, MD - Family Medicine
Avery L. Seifert, MD, FACS - Urology