I remember meeting a lady when I was 19 her last child was my age, family where very wealthy so were lucky enough to have private nursing, she didn't have a clue this was her son. I wasn't aware this was his mum, at this time. Years later he told me that it was his Mum, she had a disease that she didn't realise that he was her baby and he remembered only ever being looked after by staff due to her ill health. so it's there in every age group.