If you thought the challenges on Survivor were tough or the routes travelled on The Amazing Race circuitous, wait'll you see the gauntlet competitors face on the National Geographic Channel's Sizing Up Sperm.

Thrill as 250 million hopefuls valiantly attempt to be the first to navigate Emily's vagina in the ultimate fight-to-the-finish, winner-takes-all reality-show competition.

Eat yer heart out, Jeff Probst.