I wouldn't say any other species. Kangaroos, for instance give birth to veritable fetuses: https://youtu.be/2lCKc8tURtc?t=38s https://youtu.be/2lCKc8tURtc?t=38s

I wouldn't say any other species. Kangaroos, for instance give birth to veritable fetuses: https://youtu.be/2lCKc8tURtc?t=38s https://youtu.be/2lCKc8tURtc?t=38s Sure, I might be stretching your premise a little bit, but my point stands that evolution has a very, very wide array of tricks, and humans absolutely don't have the most underdeveloped young of any species.