Disorder: a disturbance in physical or mental health or functions; (dictionary.com) Disorders are of varying degrees. Just because medical science starts figur

Disorder: a disturbance in physical or mental health or functions; (dictionary.com) Disorders are of varying degrees. Just because medical science starts figuring out something exists in the gene pool doesn't mean it's serious enough to qualify for "filtering out". It also doesn't mean that every "disorder" has to be disabling in order to exist. Even if it did, it's a long leap to claim that it would have already been "filtered" out. Humans are dealing with a flood of more incoming data/stimuli than even 40 years ago. We have no idea if humans are actually better at handling it today than in decades past.