Caiff pobl 18 oed neu hŷn sydd wedi byw yng Nghymru am fwy na deuddeng mis, ac sy’n marw yng Nghymru, eu hystyried bellach fel pe baent wedi rhoi cydsyniad i roi organau, oni bai eu bod wedi optio allan. Mae hyn yn cael ei alw'n gydsyniad tybiedig.
People aged 18 and over who have lived in Wales for more than 12 months and who die in Wales are now regarded as having consented to organ donation unless they have opted out. This is called deemed consent.