Where we came from...

"So class, this is where we came from. The sperm and the egg from our parents fuse to become the one-cell zygote. Then the foetus grows and grows and is born to become a healthy baby!"

The teacher was giving a presentation on sex education to a room full of giggling teenagers.

Then suddenly a mocking laughter was heard and a boy stood up, shaking his head.

"Teacher, you are completely wrong!"

"What do you mean, Arthur?"

"How can a complex human being arise from just a single cell? This is utterly ridiculous. You, as a smart well-educated teacher, can tell us that a single cell, due to random chance can become the trillions of cells that make up a person?"

"But Arthur, the development process isn't just random chance..."

"Ha Ha Ha! A single cell dividing randomly will become a person? Every cell must ensure that newly divided cells must be in the exactly correct position. And the next cell must ensure that too. And the next... there are trillions of cells! The probability is one in ten kazillion!"

"No Arthur, the absolute position is not critical..."

"HA HA HA! Don't you realize that human beings are exactly like mechanical watches? We have millions of parts that must fit together perfectly to function - it is irreducible! If your lungs are growing faster than your ribs, you will explode! If your heart is growing slower, then your blood vessels cannot reach your brain! Everything is perfect!"

"Wait a second. Arthur, aren't you growing? You are much taller than you were last year, but your eyes growing less. Won't that make your eyeballs fall out of your sockets?

"Of course not, stupid teacher. I didn't exist last year. I was instantly created last night at 12 midnight, fully formed and completely perfect."