Take a look at the following creationist article about the evolution of sexual reproduction. The authors describe sex as a costly and extravagent way to reproduce. This made me wonder why they think an intelligent designer would create something so inefficent! Nevertheless, natural selection predicts that sex must provide some advantage-otherwise it wouldn't have evolved. There have been a few different proposals put forth, but lately the "Red Queen" hypothesis looks the best, since their is experimental evidence supporting it:
"Scientists from Rutgers University in New Jersey have tested this idea by observing different groups of small fish called topminnow in Mexico. Some populations of the topminnow reproduce sexually, while others reproduce asexually, so they provide the perfect opportunity to test these ideas. The topminnow is under constant attack by a parasite, a worm that causes something called black-spot disease.
The researchers found that identical populations ("clones") of the asexually reproducing topminnows harbored many more black-spot worms than did those producing sexually, a finding that fit the Red Queen hypothesis: The sexual topminnows could devise new defenses faster by recombination than the asexually producing clones." (Found at PBS.org)
A stepwise scenario for the evolution of sex is not hard at all to construct:
My explanation
This is the power of evolution and the failure of creationism: We can make testable predictions with evolution, but we cannot make such powerful predictions with creationism.
