Probability of being conceived

Previously:
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I was just thinking, what actually are the odds of being born??? I am going to work this out, and then get back to you, dearest bolo.
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I’m back, and it has only taken me a month! I have pondered this and come up with the table below (click it to see in detail), complete with reference addresses. It’s not exactly the Lancet, but fuck it, I throw it open to mighty bolo for peer review. Now I just have to decide whether to post it on the office intranet at work.

That makes the chance of being born (without considering the probability of your parents meeting and having children) 3.5 thousand millionths of a percent. It is probably also worth noting that to do a real calculation, you would not only have to work out the chances of your parents meeting and having you, but you would also have to work out the chances of their parents having them and so on, ad infinitum, back in time to the birth of life on Earth around 2 billion years ago (or even the birth of the universe?)
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Update:
I now make it 2 hundred billionths of a percent, as I hadn’t taken into account the number of combinations of sperm and egg. Obviously though, this method is still severly flawed, but it is better than saying the odds are ‘pretty slim’ with no qualification of how stupidly slim they are!