
You may have heard “sperm” and “semen” used interchangeably, but guess what? They are not the same. These two terms are often confused, despite playing different roles in reproduction.
What is sperm?
Sperm are tiny cells in the male’s body that are responsible for fertilising a female egg. These cells carry half of the genetic material needed to make a baby. You can think of them as seeds for the baby. Each sperm has a head, piece, and tail. These cells are so small that they can only be seen under a microscope. They resemble tadpoles and swim towards the eggs during reproduction.
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What is semen?
Semen is a fluid that carries the sperm. It’s a thick, white, or cloudy liquid that comes out of the penis during ejaculation. You can think of semen as a vehicle or transport system for your sperm. It is made of sperm cell fluids from the prostate gland and other nutrients and enzymes. Together, all these components ensure that the sperm remain alive, protected, and energised to reach the egg. In short, sperm are living cells, and semen is the fluid mixture that carries all those cells.
Sperm vs. semen: The big difference
Feature | Sperm | Semen |
What is it? | A cell that can fertilise an egg | A fluid that carries sperm |
Size | Very tiny, needs a microscope | Visible, thick white fluid |
Function | Fertilises the egg | Protects, nourishes, & carries sperm |
What is it a part of? | Reproductive cell | Ejaculated fluid |
Where are sperm and semen made?
Sperm is made in the testicles. The process takes around 64 days. Once they are ready, they move to the storage area called the epididymis, where they mature and wait for ejaculation. Semen is created just before ejaculation. As the sperm pass through the male reproductive system, they mix with the fluids from the seminal vesicles, prostate glands, and other glands. This combination is the final semen fluid.

How do sperm and semen work together?
When you ejaculate during sex or masturbation, sperm are released from the testicles. They mix with prostate and other gland fluids to form semen, which exits via the penis. If it enters the vagina, sperm starts swimming towards the eggs. Once the sperm successfully meets the egg and fertilises it, pregnancy can occur.
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It’s important to understand that sperm are tiny cells that help make babies, while semen is the fluid that carries and supports them during ejaculation. They work together as a part of the male reproductive system. Knowing the difference can help you be informed about your body’s fertility and overall health.