Sorry for the lofty sounding title, but I could not resist that play on Darwin's On the Origin of Species. Readers often ask where the idea for a story came from, as if a story germinates from a single seed and grows into the beautiful flowering tree presented to the reader. For me at least, the process is not that neat and tidy. It's more like a mixed orchard with many different kinds of trees sprouting and growing and in some cases withering along the way to the final product. A great deal of pruning (maybe even hacking) takes place to shape the trees into a coherent whole.
Sometimes I can recall the idea that germinated that initial seedling. Sometimes I'm reluctant to voice that idea because it sounds less than impressive. For example, my story "Saul" began with two strangers in a room waiting for a train. The man asks the woman if she is a believer. If you're familiar with 80s pop music, you'll recognize the similarity to Journey's "Don't Stop Believin'." I worked forward from that encounter. Fortunately a lot of new trees with many Biblical references sprouted along the way and that initial source was thoroughly obscured to everyone but me. My story "Gethsemane," about a man who escapes from a hellish prison and then meets Jesus, also owes a debt to 80s pop. In this case the line "Can you help me" from Pink Floyd's "Hey You" provided the first seed. I started with a man calling to another for help and worked backwards. Aleksandr Solzhenitsyn's One Day in the Life of Ivan Denisovich provided the seed for the prison.
So, if there are any other writers out there reading this, where do your ideas come from?