[edge919]

In terms of citizenship, and losing it as a child, I think the pertinent decision is Perkins v Elg:

Yes, I already said it was a 20th century invention, which when the Perkins v. Elg case was heard. Of course, the particulars in this case are not the same as adopting a child into a country that does not recognize dual citizenship.

[Mr Rogers]

POTENTIALLY EXPATRIATING ACTS

Section 349 of the Immigration and Nationality Act (8 U.S.C. 1481), as amended, states that U.S. citizens are subject to loss of citizenship if they perform certain specified acts voluntarily and with the intention to relinquish U.S. citizenship. Briefly stated, these acts include:

1. obtaining naturalization in a foreign state (Sec. 349 (a) (1) INA);
2. taking an oath, affirmation or other formal declaration to a foreign state or its political subdivisions (Sec. 349 (a) (2) INA);
3. entering or serving in the armed forces of a foreign state engaged in hostilities against the U.S. or serving as a commissioned or non-commissioned officer in the armed forces of a foreign state (Sec. 349 (a) (3) INA);
4. accepting employment with a foreign government if (a) one has the nationality of that foreign state or (b) an oath or declaration of allegiance is required in accepting the position (Sec. 349 (a) (4) INA);
5. formally renouncing U.S. citizenship before a U.S. diplomatic or consular officer outside the United States (sec. 349 (a) (5) INA);
6. formally renouncing U.S. citizenship within the U.S. (but only under strict, narrow statutory conditions) (Sec. 349 (a) (6) INA);
7. conviction for an act of treason (Sec. 349 (a) (7) INA).

ADMINISTRATIVE STANDARD OF EVIDENCE

As already noted, the actions listed above can cause loss of U.S. citizenship only if performed voluntarily and with the intention of relinquishing U.S. citizenship. The Department has a uniform administrative standard of evidence based on the premise that U.S. citizens intend to retain United States citizenship when they obtain naturalization in a foreign state, subscribe to a declaration of allegiance to a foreign state, serve in the armed forces of a foreign state not engaged in hostilities with the United States, or accept non-policy level employment with a foreign government.

http://travel.state.gov/law/citizenship/citizenship_778.html