I was wondering for a long time if a stateless person is found in the EU under 18 with no documents at all, claim to be born in the US can be deported to the US ? I searched in US laws and conventions but I can't find anything on this particular position ! If this stateless person (under 18) is born and lived in the US for is entire life is found by the EU (local police of the country like France, Germany...) authorities can be automatically or ask to be deported to the US with no documents/proof that this person is born (and normaly a US citizen), will be deported to US soil or US ambassy/consulate ? Can the US denied acces to the child to go "home" or he has to stay in the EU country (even if he don't want to stay in the EU) ? I'm at my first year in foreign laws college in France and that would really help me if someone can respond to this particular case.
Your scenario as written is impossible. If one is born in the US, then they cannot lose their citizenship before they turn 18 (and it is rather difficult to lose it accidentally; in order to lose de solis citizenship in the US, one must "intentionally revoke it"; generally speaking, you have to go to a US consulate (in another country) and formally renounce your citizenship. Additionally, the US will not accept the resignation your citizenship if you do not have a different one (i.e. if accepting the resignation will render you stateless).