On average, the male reproductive system produces about 12 billion sperm per month. Over an average male’s reproductive timeline, let’s say from age 18-35, that’s 2448 billion sperm.
Females only churn out one egg or so per month, so this is, over the same timeline, 204 eggs.
Now we consider that there are oh, 6 billion people in the world. Let’s say it’s a 50/50 male to female ratio. That means, if done randomly, the chances of your mom and your dad mating are 1 in 9 billion.
So let’s toss all the numbers together. First, your mom and dad gotta mate. That’s, as I said, 1 in 9 billion. Then, the one specific sperm and the one specific egg have to get together that created you. This is, oh, 1 in 499392 billion. Throw these two numbers together, and we find out that the chances of the genetic you appearing in just the way you did is 1 in 4.494528 × 10^24. Maybe x 10^33. My statistics math is a little fuzzy. To put this in perspective, there are only 3 to 7 × 10^22 stars in the universe. And there are a shit-ton of stars: consider how many galaxies upon GALAXIES there are even in this tiny picture (even that is a postage stamp portion of the sky), and how many many many stars make up even one tiny galaxy. The chances of you happening are less than picking one of those stars at random.
On that note, the chances of you happening are also about 1.6 × 10^15 times worse than your chance of winning the lottery. Makes that $1 seem well spent.
My point here is I get irked when someone proves that something couldn’t happen by quoting the odds. Sure, maybe the chance of life forming spontaneousely are astronomically small, but so are the chances of you, and heck, you happened (hopefully). The chances of almost everything that happens are astronomically small when you consider everything that possibly could happen. But with all the stars and all the planets and all the parrallel universes and all the time it was allotted (Think about it. Billions of years here.), why couldn’t it have just happened?
