Polyspermy

Polyspermy is when too many sperm cells try to fertilize one egg cell. It's kind of like trying to fit too many people in one very small room.

When a person with ovaries releases an egg cell, many sperm cells from a person with testes try to reach the egg cell as fast as they can. They swim really hard and fast to get there first. But only one sperm cell can fertilize the egg cell, otherwise things will get too crowded and messy.

If more than one sperm cell enters the egg cell, this can cause big problems because too much genetic material gets mixed up all at once. It's like trying to cook too many things at once without a recipe, and not knowing what the end result will be.

So, sometimes our bodies put up defenses to keep multiple sperm cells from fertilizing one egg cell. These defenses can include things like thicker egg cell walls or chemical signals that tell the sperm cells to slow down or stop.

Polyspermy is not a good thing in humans or most other animals, and can lead to things like birth defects or miscarriages. So it's important that only one sperm cell fertilizes one egg cell, and that everyone waits their turn.