I love to point out the irony that natural selection, often said to be the driving force of, and even synonymous with Evolution is actually the greatest reason it simply can't happen. All living organisms, great and small, are extremely complex. Some features are relatively inconsequential, such as the color of your dog. You can have a white dog, a black dog, and all the colors in between, it doesn't matter because a dog's color has no effect on its survival.
The same cannot be said for other features. I often like to look at the heart as an example. The heart, of course, is a vital organ for all animals in which it features. If it is faulty, the best one can hope for is that it is not so faulty as to be instantly fatal. The heart is extremely complex, and cannot evolve gradually because any transitional form between a creature without a heart and a creature with a heart simply could not survive, much less compete with its ancestors. This, of course, is ignoring the fact that a heart needs more than to just exist and be fully functioning in order to be of use. Other organs, the nervous system and all the blood vessels, must be fully formed, fully functioning and in their correct places to work together.
But that's just one organism at a time. Most creatures are not radically different between the two genders. But genders themselves are. A male and a female naturally have different anatomy in order to perform their necessary functions. The chances of forming the regular systems common to both genders is unthinkable, to say the least, but in order for sexual reproduction to be a thing, the first sexually reproducing species would have had to have been perfectly formed immediately. Even with an anatomically intact female, the species could not evolve without an anatomically intact male. Similarly, an anatomically intact male would be useless without an anatomically intact female.
Therefore, the very existence of sex utterly refutes Evolution because natural selection would work against every attempt to get it right. Only if God made us male and female in the beginning could sex exist.