Summary
This video describes how a woman's immune system attacks sperm, treating them as foreign invaders, and how only a few sperm survive the journey to the fallopian tube.
Highlights
Sperm as unwanted invaders
00:00:03
Sperm are considered foreign to a woman's body and are treated as unwanted invaders, triggering her immune system.
Immune system ambush
00:00:13
Once sperm enter the cervix, they face a labyrinth of dead ends, perfect for an ambush by white blood cells that attack from all directions.
Survival rate
00:00:55
Out of an original 250 million sperm, only as few as 20 may survive to reach the safety of a fallopian tube.