I find that being a transracial adopted person, with international roots, has not hurt thinking in a ways beyond local norms. My adoptive parents were Episcopal Christians and I remain an Episcopal Christian (in fact am an Episcopal priest), but they were a little upset that I was reading what I was and asking about things like reincarnation. Christianity has insisted for many centuries that the human being originates in God and comes to birth only once. Death happens only once. There are a few passages in the New Testament that suggest that in those ancient times, other thoughts and feelings existed that allowed more complex ways of thinking about identity. For example, the apostles were free to tell Jesus who some people believed him to be: John the baptist, Jeremiah or some other prophet.
Judaism was in general less concerned with previous lives than one’s coming from God and God’s in-working with the body, like a potter with clay. Some from that period were concerned with reincarnation, even in the west. In the east, reincarnation is normal and the basic human problem is seen in terms of birth. The goal is to escape the wheel of birth. Leaving aside all considerations of karma that lend credibility to the notion that adoption is a sort of punishment for past sins, does a notion that human beings are eternal and that particular incarnations manifest a continuity (with freedom) across ages and world epochs help or hinder one coming to rest with the facts of losing first parents and landing in strange environments? In other words, if human nature spans many lifetimes, how one relates to particular historical events and experiences is put in a larger context. The larger context may not make anything magically feel better, but does it offer a wider and helpful line of inquiry towards self-discovery?