I was having a discussion about the evidence for and against evolution. I brought up the fact that Humans have one less pair of chromosomes as a result of the fusion of two ape chromosomes and all the evidence that supports this. Someone then told me that this is 'rubbish', because: 1) If a member of a species suddenly had 2 of it's chromosomes fused, it would be rendered incapable of mating with the other members of that species. The mutation would then die with this creature as it could not have children with such a drastic change. If by some unlikely chance that a twin male and female were born from the same mother with the same mutation, it would not be possible for those two to mate with each other and continue to have their descendents mate with each other to populate the earth with Humans that had this mutation 2) It's impossible for chromosomes to even fuse in the first place as they aren't designed to do that. He then went on to compare it to pressing two ends of a magnet together and having them repell - chromosomes just can't fuse Are either of his two points valid? If not, can someone explain why not so I can educate myself and then him in the process?