My brother and sister have both been diagnosed as adults. My brother lives abroad, and his diagnosis does not seem to be based on DSM5/ICD, I can look back with him and see elements in childhood though. My sister has been diagnosed here, when she has spoken to me about behaviours that have led to diagnosis, and i don't recall these things being as obvious in childhood as my bother, and it doesn't feel to me more like anything that I think most people would experience, but I suppose it's the whole picture coming together and girls presenting differently? Both my brother and sister are graduates with jobs and long term relationships, sister has children.
My dad I think may well have ADHD, he also has severe MH issues and addiction issues which I imagine would make it all difficult to unpick, but he would fall into the category of someone who isn't able to function and where it has had a massive impact on his life.
I do agree with PP that I often feel I would meet a lot of criteria - but it's because of life circumstances that it's hard to cope - working often until midnight, kids, DS on patheay for ASD assessment and has other serious health condition, house needing a lot of work done and generally chaos, elderly parents for both me and DH needing support - when life was simpler and it was just me or me and DH I managed fine.
I would be interested if there are people who do read a lot of the ADHD and ASD traits and think nope, none of that sounds like me? I have long recognised myself as an introvert with social anxiety, so there is some crossover with lists of autism traits - but having had DS, I can see the differences between 'everybody does this a bit' and 'really causes a problem' in these.
I do think it's interesting how many people seem to want to identify with these diagnoses - why? I agree with PP comparisons with OCD, people seem to want to want claim these conditions without really understanding what they are and how they really impact on people.