My ggrandparents came To the US with two children, a boy and a girl. The boy never attempted to hide his foreign birth. The girl, who was a few years younger, changed her date of birth to make it appear she was born after her parents’ arrival. Why?
Well, we do know that prejudice against immigrants was very common in the US at the time she was growing up, so we suspect she just wanted to fit in and be accepted by her schoolmates instead of being rejected and bullied as she would have been had they known she was one of those terrible “foreigners” who were overrunning the country and destroying its culture.
It was only after she had been dead for decades that we found her original birth registration in the foreign records. Even then we weren’t sure it was the record of *her* birth. Her oarents might have lost that child in infancy and reused the name for another daughter born a few years later in the US, but after exhaustive research in both countries we have been unable to uncover even one shred of evidence of the foreign-born child’s death, or of the birth of any other child who is not fully accounted for, so the only reasonable conclusion is that she was that child who was born in the old country several years before the birthdate she adopted after arriving in the US.