My cousin does a lot of genealogy stuff and has traced our great great great grandfather (I think) and now says we are not (for example) Smiths, but actually (for example) Morgans, because this shared ancestor was born Morgan and adopted (unofficially perhaps?) by Smiths.
Is this correct? Seems to me we've been Smiths for long enough to be Smiths! My mother took my father's name on marriage so we're BaMammas, but we're also Smiths because that's the larger family group.
I also wonder how this impacts my cousin's adopted siblings, are they 'not really' Smiths, but actually WhateverTheirMotherOrFatherWas?