In 1972, a Colombian psychiatrist asserted that being a hippie is a form of mental illness that can be passed on to one's children. Apparently a fondness for patchouli and Iron Butterfly can be traced to your chromosomes.
Vaughan Bell of Mind Hacks found the book Psicopatologia y Existencia del Hippie ("Psychopathology and Existence of the Hippy") by Miguel Echeverry at his local library. Bell was terrifically amused by Dr. Echeverry's claims that the hippie lifestyle was a mental disorder that scars one's DNA:
The book contains not a single reference to any scientific or clinical study, although is happy to wax lyrical about the subgroups of the hippy mental illness. Apparently, there are five: hippies with defective personal relationships and autistic-like problems, aggressive hippies, hippies with defective behaviour and poor family adjustment, emotionally impaired hippies, and those with abnormal, perverted or inverted instincts.
For those worried that he may be getting a little too psychoanalytic, Dr Echeverry makes it clear that there is both a strong environmental and genetic component to hippy psychopathology. Yes, apparently, you can inherit hippidom.
You can read more about this quirky psychiatric tome over at Mind Hacks.