"Watch this video and sign this petition if you know that a human life won't become a donkey or a cat."
When Rubio appeared on CNN after Thursday night's Republican debate, he kept insisting that this vague entity called "science" has declared that human life begins at conception. (Actual biologists, for what it's worth, argue that life is continuous and that a fertilized egg is no more or less alive than a sperm or an unfertilized egg.) CNN host Chris Cuomo vainly tried to point out that "science" says no such thing, and Rubio got a little excited. "Let me interrupt you. Science has -- absolutely it has. Science has decided... Science has concluded that -- absolutely it has. What else can it be?" he asked. Then Rubio reared up for what he clearly intended as his wowza line: "It cannot turn into an animal. It can't turn into a donkey. The only thing that that can become is a human being."