I believe I've spotted a flaw, and I'd like to know if other fans have noticed it too.
In the first BTTF, Marty McFly travels back to 1955 (his parents' high school era).
He meets his mother and she has the "hots" for him.
He helps his dad, George.
And then he goes back to 1985 (his present day) and see's that everything is different, having been affected by his doings in 1955.
Surely, as Lorraine and George had their son born (Marty) and he started to grow up, wouldn't they think, "Hang on... He kinda looks like that kid Calvin Klein that we knew back when we were in high school!"
Is that right? Or am I missing something?
DISCLAIMER: I like BTTF, please don't take the following as a general criticism of the movie.