Evolution: Gender Cannot Be Explained

No observable, testable, measurable, repeatable evidence exists to explain how male and female evolved from asexual organisms. Evolutionary biologists have been unable to determine the origin of sexual reproduction, sperm and egg, or a mechanism that might cause such a mutation.

That doesn't prevent the "Wonders of the Scientifically Fantastical" sci-fi stories from being spun. But still, not a shred or speck of hard scientific evidence.

Discuss.