I always thought of that as a distinct possibility. It would explain the generally humanoid appearance that people describe when they meet aliens.
I don't know what I'd do if I could move though time. I might go back to something piddling like a year ago so I could see how I really was back then and make improvements, or more likely into the future. Near future only though, I wouldn't feel safe going more than 50 years forward. I don't give this planet good odds past that point.