The child of 2 U. S. citizens would be a citizen regardless of where he was born. You quote a current law, but I am going from what I was taught at the Federal law Enforcement Training Center at Glynco GA during the Immigration portion of my training at the US Customs Academy in 1985. The course was taught by our Chief Counsel lawyers. They can’t apply a new law that would deprive him of his rights, when it wasn’t passed until many years after he was here.
He is a U. S. Citizen.
For persons born between December 24, 1952 and November 14, 1986, a person is a U.S. citizen if all of the following are true (except if born out-of-wedlock)[7]:
The person's parents were married at the time of birth
One of the person's parents was a U.S. citizen when the person was born
The citizen parent lived at least ten years in the United States before the child's birth;
A minimum of 5 of these 10 years in the United States were after the citizen parent's 14th birthday.
I don't know that any of this pertains to him, however, it's not so simply cut and dried that the only stipulation is that the parents be citizens (which is the ONLY point I'm making). This comes from:
http://en.wikipedia.org/wiki/United_States_nationality_law#Birth_abroad_to_two_United_States_citizens
Which of course could be wrong, and the law prior to 1952 I do not know. You are free to show me more links, it's difficult to find info.