People always bring up Xavier's weird crush on 15-year-old Jean, but forget that Xavier was supposed to be around 28 at the time, given that he was 18 when he served in the Korea war, which ended ten years prior. He was bald because of his powers and disabled because an alien threw a rock at him, not due to old age.

Still highly inappropriate, so much Marvel nixed it pretty quickly, but the "dirty old man" trope doesn't really apply.