EDIT: The original question for this Writer's Block was something like "if a baby of unknown origin was left on your doorstep would you keep it?" I think it's pretty funny that LJ has changed it since then, because it made my response absolute nonsense!
I would do the right thing. Care for the baby, make sure s/he's healthy, and contact the proper channels. Keeping the child would not be an option without doing so -- so many legal issues come into play when a baby is abandoned. You need a birth certificate to get a Social Security number, and you need a SSN to get a job, and you need a job to survive... why sabotage his/her future from the get-go?
Yeah, I like kids. Sue me. Living in this town it's the exception rather than the norm. I constantly battle with wanting to have a family AND friends. I get the impression I can't have both.