I just want to say, mutants as a whole are pretty awful when it comes to actually, like, reproducing and being successful as a species. Like Mercury and Glob who can't reproduce at all. While Logan seems to have be able to have children, it's questionable if Laura would be able to given how the female body works. Her body would kill any sperm and would probably make a viable pregnancy impossible.

While humans also have to deal with fertility problems, mutants would have to work around these in far greater numbers. Eventually, you'd likely just have a couple of mutants breeding, creating a situation rife for genetic bottle-necking.