Why does sex exist?

For three billion years, life on Earth did well enough without it. A reproducing organism simply divided, thus arranging for its posterity to be carried on by two almost-perfect copies.

That “almost” was crucial. In nature, true perfection is a blind alley, leading to extinction. Slight variations, acted on by selection, let even single-cell species adapt to a changing world. Still, despite eons of biochemical innovation, progress was slow. Life remained meek and simple till just half a billion years ago, when it made a breakthrough.

Bacteria were already swapping genetic information, in a crude fashion. Now the system of exchange got organized, increasing patterned variability ten thousand-fold. Sex was born, and soon came many-celled organisms—fish, trees, dinosaurs, humans. Sex did all that.

Yet, because nature accomplished something in a certain way, must we follow suit when we design our new humanity? Modern gene-craft can outpace sex another thousand-fold. Within overall mammalian limitations, we can paint with colors never known to poor, blind biology.

We can learn from Mother Nature’s mistakes, and do a better job.