Synaaron, I just heard the song for the first time and my first thought was the 5 generations thing too! 4 possible explanations: 1) great granddaughter used a time machine 120 years from now to fly ahead 872 years into the future; 2) Humans discover a way to live to 250 and give birth at age 200; 3) Discover how to live to 250, but adopt at age 200; 4) g-g-g granddaughter born in 120 years or so, and she lives to be 1000 or more, as humans discover the secret of living (nearly) forever. I'm sure J Bros were thinking of one of these solutions to their conundrum when they performed this song! Lol!