20,000 years ago...
*Snot drools from nose*
"Heh... heh... have sex with me or... or... you will be killed.... ermm not by me but... by the gods.... no... THE GOD.... and you will... *wheezes* be tormented forever!"
"So... you hear the will of this... god who can kill me?"
"YES! God speaks to me when I'm painting in the back of my mother's cave! OBEY GOD'S WILL!"
"Ermm... I better not risk dying... god's will be done then..."
Then he realises he might only have sex with her once.
"Also, no condoms or birth control plants. GOD WANTS YOU TO MAKE BABIES! Now get pregnant and barefoot."
"Why would god want me pregnant all the time?"
"It's YOUR DUTY... because god is a man, the ALPHA MALE, and HE wants YOU to be happy with babies!"
"Oh... that makes sense..."
- - -
That's right kids, religion was started by the neolithic equivalent of a World of Warcraft junkie.