Well I'm no expert, but I do know that astrology doesn't predict a thing. Astrology is a description, not a prediction. That's been explained several times already on this thread. So the answer's no, Bagpuss. Sure, those babies would have similar charts, but even 10 minutes difference in birthtime or a 20-mile difference in location makes for significant changes as we've seen. And as Ivor explained above, those charts display tendencies, or potentials, which may or may not ever be realized by the individual.