Why can't humans create another human

There's a lot of debate around when ai will simulate human intelligence, but it's a fact that humans already have created creatures with a simular intelligence, like apes, but what's the actual difference in our intelligence? The reason we are able to create apes and some other animals with human simular intelligence is that we have the source code, basically the blue print how to create such a creature. But we don't have humans blue print, and that's why it's so hard to replicate it. So that's why I think that it's not that important when ai will reach human intelligence, but more important when humans actually will be able to replicate itself. What do you think?