Clan adoption across ethnic lines is not unheard of. I know a Japanese gentleman who was officially "adopted" into Clan Elliott by its chief twenty-odd years ago. Likewise, colour has little bearing on being Scottish, as evidenced by the former Secretary of State for the United States of America, Colin Powell, being granted arms by Lord Lyon on the basis of his Scottish ancestry.

The question concerning adoption within a family raises a different question. A Russian baby boy adopted into an Irish family would retain his descent, despite having an Irish surname. He might become "culturally" Irish, but not Irish in an "ethnic" sense. However, if he married an Irish girl, their children would be "ethnically" Irish (as well as "ethnically" Russian).

From a strictly heraldic point of view the adopted child would inherit his adoptive father's arms, but with a suitable charge placed on the arms indicating the adopted status of the individual. This is a rather recent development in heraldry, and not all jurisdictions have resolved this matter with the simplicity of College of Arms who now mark the arms of adopted children with a special charge composed of two links of a chain.