PrimeWire

You can now watch the entire National Geographic: Sizing Up Sperm movie online in high-definition quality, complete with English subtitles for a better viewing experience. Best of all, there’s no need to download anything—simply stream it directly from your device anytime, anywhere.

Each of us was the grand prize in an ultimate reality competition, the amazing race a sperm makes on the road to fertilization. Millions of sperm compete while overcoming armies of antibodies, treacherous terrain and impossible odds to reach their single-minded goal. To illustrate the full weight of the challenge, Sizing Up Sperm uses real people to represent 250 million sperm on their marathon quest to be first to reach a single egg.