If you are a book character*, especially in a paranormal and you - say, decide to have sex in front of a centuries old fertility statue, assume that your previous issues with conception will no longer apply.
Also, if you have sex with an alien, please assume that your Earth birth control will not be effective, because, you know, it's for Earthlings. It has not been tested on aliens.
*These rules may very well apply to non-fictional people to, I am simply less certain of that.
Rants About New (and old) Things
