Interesting. The Constitution is pretty clear here -- if you're born on US soil, you're a US citizen. However, there's no requirement that the State Dept. issue visas to people who are 6-9 months pregnant.
Actually there IS debate about what that section actually means. Some take to mean in context that your parents had to have been under the laws (a citizen) already and subsequently you cannot just hop the border, have a baby, and the baby is a citizen. I happen to believe that as well.
Oops, left out the citation: US v. Wong Kim Ark, 169 US 649. http://scholar.google.com/scholar_case?case=3381955771263111...
My grandmother was born in the US. Her mother died when she was young, so she and some of her siblings were sent back to the old country to live with relatives for a while. Eventually my grandmother and her siblings returned to the US, and she married my grandfather, leading to me, a proud American.
The reason this law was important was because my great-grandparents weren't US citizens. In fact, they were prohibited from becoming naturalized US citizens even if they wanted to be ( http://en.wikipedia.org/wiki/Naturalization_Act_of_1790 ). Without the 14th amendment, I might not be a US citizen.
Nor would my great-uncle, who served in the US military. It turns out that in 1940 the US military suspected they had a need for Japanese translators. What better way to learn Japanese than to have gone to school in Japan?
My last thought on this topic is a joke:
Q: Who was the greatest German general of World War II?
A: Eisenhower.