And the number of planets is not complete yet. The astronomers expect a tenth planet, which is too dark to see now. So astrologers, who base their predictions on the planets have many problems too. Other astronomers are occupied in determining someones character or personality. But character descriptions with reference to the moment of ones birth and the relevant position of planets is problematic.
Identical twins have an almost identical character.
However they are not always born at the same time. Often their moments of birth differ in time. It even occurs that their birth takes place on two different calendar days. Seen from an astronomical viewpoint, such twins should have diferent characters. With non-identical twins the problem is exactly the opposite.