system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it impossible for a human/animal to breed with another species?

Bit of a weird one, just would like to know the science behind it.
gpt
Your genes are basically a recipe for making you, and are created by combining the recipes for making your parents into a new receipe.

When two recipes are close, like German chocolate cake and red velvet cake, when you combine them together, you are skill likely to get some kind of cake, even if it is an unusual one no one has seen before.  But if the recipes are too different, like German chocolate cake and chicken cacciatore, all you will get is some inedible mess.

Your genes work the same way, you can only make a new creature if the recipes for the parents are very similar.