But if someone wants to argue that there might be some character traits associated with being born (or conceived) at certain times of the year, I'm not going to dismiss it out of hand.
The catch being that the months of birth or conception wouldn't be consistent across the globe if the influence on birth outcome and health were tied to the seasons. I read somewhere that those born in late fall through mid-winter were more prone to depression. If it were due to low levels of daylight at the time of birth, wouldn't that only hold true for those born in the northern hemisphere? If people conceived during a time of plenty (summer when crops are growing) and then born in spring when food resources are once again abundant, would they be any healthier or have more of a proclivity for some skill than those born at the equator where seasonal differences are minimal? These days with people being quite removed from the environment and seasonal food cycles, I'd say seasonal impact is even less than any other time it could have been relevant. I think astrology is fun as a passing entertainment, but month of birth or conception could only have at most locally-significant impact on behavior or health.