I am the mother of a seven-year-old boy, and I work in child abuse prevention, so I am hypersensitive to issues related to sexual abuse and incest. I did not find these themes even to be present in "Back to the Future," much less offensively so.
Why shouldn't a mother--aware or not--find her teen-aged son charming? I should hope she would admire qualities in him--after all, she worked her tail off to instill those very qualities.
And Marty probably reminded his teen-aged mom, indirectly, of his father and possibly of her father and even of herself. The two of them never even came close to touching inappropriately.
"Back to the Future" was an inventive, positive, well acted, well executed, heartfelt movie. I only hope people seek a second opinion on this one--their own!
ELIZA GARRETT SIMONS