OK I went further back, to when they codified the various immigration laws into a more cohesive state. Its the McCarran Act, aka the 1952 immigration and nationality act. Pertinent section is Title 3 chapter 3.
Date and reference is 66 stat public law 414 June 27 1952.
Page 267 is where chapter 3 starts.
Synopsis of section 349 (a) (1) which deals with loss of nationality:
Nationality can be lost if the person got naturalized elsewhere by applying for it on their own.
Nationality can be lost if they got naturalized elsewhere on account of having an app done on their behalf by a parent.
Nationality can be lost if they got naturalized elsewhere on account of their parent getting naturalized elsewhere.
the above items will occur PROVIDED the following happens:
Parent nationalized elsewhere while the person was under 21.
Parent did a nationalization elsewhere on their behalf while the person was under 21.
The persons nationality WILL be lost if they don’t come back to the u.s. and establish residency before they turn 25.
Page 272 says that a person with u.s. nationality that is under 21 and is resident in a foreign state with a parent who loses u.s. nationality through section 350 or 352 will also lose their nationality if they get foreign nationality and don’t establish residency in the u.s. before 25 years old.
I will look at sections 350 and 352 and see what they say about the parent(s), and post later.
One of the copies of the act that I downloaded has amendments up to around 1997; I will pore through it to see what changes were made that may have affected a person born in 1961...
All of the above is applicable ONLY if the person were a u.s. citizen to begin with, (or maybe got naturalized at some point) before going abroad.