There is this one question that has resided in my mind for a long time.  Thought I'd present it at Sajha, so maybe intelligent folks here can put forward their opinion on it.

The matter relates to astrology - Nepali ma jyotish saastra.  It seems, in this field, everything emanates from the time you are born.  I mean, literally, that time.  Everything hinges on the precise day and time of the person's birth. 

My question: WHY?

Someone said that maybe because when the child is born, the very first rays from planets (graha-haru) determines that child's attitude and future. 

But WHY?

If those all powerful rays from different planets should effect the child, why should the time of birth be so significant?  I am sure those planets would have as much effect when that child is in the womb, in as much as when s/he is out of it.

Does anybody know?

Disclaimer: I am somewhat skeptical of the astrology/jyotishi mumbo-jumbo.  But I am trying to keep an open mind.  Nonetheless, being a rationalist, I need to know WHY.