Karma is a complex concept which, because I come from a mainstream Christian upbringing, I am learning through the work of others. Karma was not in the Colorado cultural air I breathed growing-up, though it has been making inroads to the western mind for decades. To make a general statement, Christians (and Episcopalians, I am one, as a subgroup) do not know what to do with the notion. Karma is entertained but kept as a mere hypothesis. Western Anthroposophic circles present a comprehensive view of reincarnation which is what I have in mind here.
Anyway, adoptees (and donor-conceived persons) may discover karmic confusions resulting from adoption and DC practices. Ancestors and karmic relationships which are known to souls approaching incarnation are lost and/or confused by the resulting dislocation and prevention of basic self-knowledge. This might affect many areas of a life and may be one way of conceptualizing “genealogical bewilderment”. The significance of these practices may reach beyond death as well. Death is sometimes seen, at least in part, as a reunion with ancestors. Death, of course, is more than just a meeting of ancestors; but the karma of death is possibly changed in random ways.
I am only able to raise the question whether the practices of adoption and donor conception may be affecting the karmic structure of human life. Adoption (and DC) are significant for our life on earth but may also be affecting our pre-birth and after-death karma.