'The Great Sperm Race' tells the story of human conception as it's never been told before. With 250 million competitors, it is the most extreme race on earth and there can only be one winner.
| Actor | Role |
|---|---|
 Richard ArmitageNarrator (Voice) | Narrator (Voice) |
 Richard GloverGlenn | Glenn |
| NNatasha PringEmily | Emily |
| EEric TwightLead Sperm | Lead Sperm |
| JJaqueline WingfieldLead Sperm | Lead Sperm |