'birth relative' in relation to an adopted person means a person who, but for the adoption, would be related to him or her by blood (including half blood) or marriage
('birth relative') mewn perthynas â pherson mabwysiedig yw person a fyddai, oni bai am y mabwysiadu, yn perthyn iddo drwy waed (gan gynnwys hanner gwaed) neu drwy briodas