For people aged 16 to 24, 0.9% reported that their gender identity was different from their registered sex, compared to 0.2% of people aged 65 and over.
Ymhlith y bobl rhwng 16 a 24 oed, dywedodd 0.9% fod eu hunaniaeth o ran rhywedd yn wahanol i'r rhyw a gofrestrwyd pan gawsant eu geni, o gymharu â 0.2% o'r bobl 65 oed a throsodd.