That is something up to the child to decide or maybe his/her family because Hinduism is a religion and American is a citizenship.
That is exactly something like; if I, a Hindu and an Indian, married a Buddhist and a Japanese, the child will naturally know what Hinduism is and what Buddhism is. Moreover, he’ll be free to speak two languages naturally, Hindi and Japanese and let’s count English as well because the Hindi speaking mom and Japanese speaking dad will need a language to communicate, so the child will pick up English as, if not a native language but a natural language, speaking since childhood.
And, if we emigrate to Korea for example when the child is just 2or 3, he’ll speak Korean naturally as well because that’s the language spoken around him most of the time. Being in Korea will make him comfortable to Christianity as well.
I guess that’s the case with Anne Frank as well, but her parents were both Jews so the situation is less complicated than the one I stated.