When I was growing up in the 80s I can remember many parents of kids with autism or mental retardation or many other issues using this as an explanation “Oh the doctors say s/he must have not had enough oxygen during birth”. I can even remember people speculating their child with mild issues like learning disabilities or dyslexia must have been a tiny bit oxygen deprived during birth, which caused their issue.
Somewhere in the time since this idea has dissapeared altogether it seems, no one uses as an explanation anymore.
Why was this used to begin with? Was this an actual medical theory? Are there any other ideas like this in the medical field in recent memory that just faded away like a fad?
EDIT:I recall this was also a popular reason parents would present for the fad diagnosis at the time of ADHD or hyperactivity.