I looked at a creationist web site titled www.mathematicsofevolution.com. It was recommended to me by a creationist I was debating. At that site I found the statements shown below. "Herman" is a hypothetical "creation-scientist" [oxymoron noted]. Herman's not a real person. I would guess that it is meant to represent the author of the web page.
Herman then starts talking about the evolution of species which had both a male and female. He starts talking about how the same random mutations must occur in the germ cells (i.e. the cells involved in reproduction, meaning the sperm and eggs) in both the male and female in order to have viable offspring.
Herman likens this to two different people (who do not know each other) receiving an email with a 10,000 volume encyclopedia. Each of the two people is instructed to independently make 20,000 random word changes to their soft copy of the encyclopedia. These 20,000 word changes can be to any of the pages in any of the 10,000 volumes.
Herman states that the probability that the DNA of both a male and female germ cell having the same random mutations (and thus being able to have offspring with new genetic material) is equal to the probability that the two different people coincidentally make the same 20,000 random word changes to the 10,000 volume encyclopedia. Herman actually started laughing at such an absurd possibility.
Let's think about this a bit. Apparently the author of this web page believes that males and females reproduce and, therefore, evolve totally independently of each other. The male children get their genes ONLY from their fathers and the female children get their genes ONLY from their mothers.
**IF** that was how genetics worked then, indeed, males and females could no longer mate and produce offspring at some point. A sufficient number of mutations would, indeed, cause the males and females to be sufficiently genetically different that they could no longer mate.
But the last time I checked, that's not how genes work. In fact you get genes from both parents. So what could - and DOES - happen is that genetic changes can accumulate over time and will get passed to members of both sexes. So one genetic change gets passed onto both sexes, then another change is added which is also passed on, and so on.
If this ludicrous argument had any validity at all, we could not have multiple human races on Earth. That's because the females couldn't reasonably be expected to get the same mutations as the males. Similarly it would be utterly impossible to have many breeds of dogs and cats.
Obviously this argument is silly and ridiculous. ANYONE who accepted such an argument lacks any understanding of genetics whatsoever.
There are some creationist web sites that make arguments written by people who know something about science. The arguments aren't valid, but they make someone who knows science at least think about the arguments a bit. Answers in Genesis is such a web site. You would probably have to at least be in High School to see the faults in the AIG arguments.
But many creationist sites aren't like that. Many creationist sites are simply stupid. Laughably stupid. Many children in elementary school would laugh at them. They show an utter and complete lack of understanding of evolution. That's almost to be expected. But more strikingly they show a complete lack of understanding of ANY of the basic concepts - genetics, biology, mathematics, etc.
Visiting such sites can be a lot of fun for that very reason.