The 14th Amendment was intended to protect our Black population. It said that the Government cannot rob a citizen of their citizenship, unless they want to give it up. Then, there’s this from http://caselaw.lp.findlaw.com/data/constitution/amendment14/01.html#1:

“In a subsequent decision, however, the Court held that persons who were statutorily naturalized by being born abroad of at least one American parent could not claim the protection of the first sentence of Sec. 1 and that Congress could therefore impose a reasonable and non-arbitrary condition subsequent upon their continued retention of United States citizenship.”

The first sentence of Sec. 1 mentioned above basically says that if you are born or naturalized, you cannot be denied your citizenship.

There’s also an issue of how long the mother had lived in the US after a certain age, and before giving birth abroad, and perhaps the stated age of 14 shown today, may have been different in 1964. I have yet found that.

Berg’s lawsuit is very specific. I cannot follow it all and have idea if this is anything.

Wish I could give you a better answer.