Another home run from Ted Chiang. Almost long enough to be a novel, this is a story about AI, "sentient software", virtual creatures and our responsibility toward them. The idea is that if we are going to play gods and create sentient beings (even virtual ones) we have a moral obligation to ensure the safety and well being of the creatures we create. That they are not flesh and blood is immaterial.
The theme of responsibility for AI entities we created remind me of the "dust theory" in [b:Permutation City|156784|Permutation City|Greg Egan|http://d.gr-assets.com/books/1287341300s/156784.jpg|1270567] by Greg Egan. The AI or virtual creatures in this story are sentient living beings even though they are digital, not biological. They do have feelings and are alive in most definitions of the word you can think of. I don't want to spoil the story for you by writing too much about it. If you like Ted Chiang's [b:Stories of Your Life and Others|223380|Stories of Your Life and Others|Ted Chiang|http://d.gr-assets.com/books/1356138316s/223380.jpg|216334] anthology you have to read this, if you have never read any Ted Chiang before and you want to know what the fuss is about you can start with this (available for reading free online
Come to think of it there is no "if", you simply have to read this.