Actually I had in mind a book that faced a similar fate, “Astrogenetics” by Maurice Cotterell.
The main idea behind the book is that the stars are obviously too far away to affect us, but there is one star that is not far and DOES affect us. The sun.
The second idea was that the date of birth was not what was really important, but the day of conception was. However noone could really know where that was, so people recorded their birthday and just substracted 9 months. The scientific claim that a fully grown baby cannot really be affected much by the sun, but the very early stage of it where it is just a cell that is undergoing mitosis might be affected is valid. Any effect on those few first cells would be transferred to the rest of them. Any effects on a few cells on a grown baby, would not. So far things are very sensible.
The third idea was that the sun ( which has various magnitic poles - for lack of a better term ) has a yearly phase on how much and what kind of intensity of radiation it sends our way depending on where the earth is and whatnot … the author offers some evidence of that, but of course that is not something that could be easily and conclusively measure.
Be that as it may, the fourth idea was that the ancient astronomers at the very least thought that this was so and that this was one of the things that they were measuring for. When they were gone only the “superstition” level of the “date of birth” (which in itself is not the point, but was used only to estimate the conception) and the “zodiac signs” (which is just a marker for the sun and the stars themselves are unimportant) was left in the collective minds of the masses.
I think only the third part of the main concepts is really up to debate. The others are very reasonable.
As I think an italian phrase goes, even if it is not correct, it is a very interesting idea.