One of the stranger items to cross my desk recently -- way weirder than the article on "teeth critters" -- is a review of Frank McGillion's book BLINDED BY STARLIGHT. McGillion, a medical researcher, makes a case for an actual connection between astrology and medicine. One of his claims is that the amount of sunlight a pregnant woman receives affects fetal development through influencing her production of melatonin, vitamin D, and other bodily products. This, in turn, affects the growing fetus biologically, including brain development, which may affect personality. Since sunlight varies dramatically throughout the year in those countries in which astrology was first created, there may indeed be a factual link between birth date and personality. The original ancient-world "astrologer-physicians," McGillion says, were extremely acute observers of human nature, and the whole system of astrology thus grew from medical observations rooted in reality. "What's your sign?" is thus a meaningful biological question.
Although this seems tenuous to me, it's also fascinating. Research on meditating Buddhist monks has charted shifts in blood flow in their brains which may lead to some of the subjective aspects of the meditative experience. I make heavy use of this, in fact, in a story I recently sold to Jim Baen's Universe, my "China story," now called "First Rites." The connection between biology and belief systems is a fairly new field of research, and I find it endlessly interesting.
Incidentally, my other story for JBU, "Laws of Survival," is now up at JBU. No brain chemistry in this one, but lots of dogs and a few enigmatic robots.