chances

1 out of 1 (since it happened), or something like 1 out of 1 million (for the number of sperm), or something like 1 out of a trillion billion (for your parents meeting each other, having sex, then all the sperm and so on)

What exactly are the chances of getting 3 aces on the flop, and me having the last ace in the deck?

I mean assuming materialism is true. Did my parents need to be born and to form a sexual relationship? But that of course is absurd because each of them would need to have had their parents to have been born and to have met up; and the same going back to when first life appeared on Earth...

...are 909,000 to 1 http://story.news.yahoo.com/news?tmpl=story&u=/ap/20030902/ap_on_sc/britain_asteroid_watch_1 How do you calculate odd like that? It seems awfully exact.