allow to birth? Only God does that. US does entice tourists by granting citizenship to anybody born on US territory. If you don't like it - change the Constitution. If you aren't changing it, then you want it for some reason.

Edit: to the commenter below - what "moral" has to do with the Constitution provision? I mean beside the general understanding that Constitution is a law and following law is in general a moral thing, and that US Constitution was generally an attempt to write a good moral thing.

I first have to ask: do you personally think it makes sense that couples can enter the US illegally, remain in the US illegally until a child is born, and have that child automatically become a citizen? Do you think it is moral? Why?

But just to clarify, GP was asking you whether that particular path to citizenship exists in other developed countries.