Firstly, I want to thank all of you for posting your stories up here. While sad and sometimes horrible, they are educational and hopefully will do some good for others to hear.
I really hope this doesn't qualify as off-topic, since it isn't technically a story in which I breed a litter, but here goes anyways.
I have 2 female rats, Bean and Gus, both from a local petstore. Gus is outwardly, very healthy; never a sneeze, extremely laid back and cuddly, eats well, etc. Bean has and always will be a runt. She's about half the size of gus and her body would barely stretch from the palm of your hand to the tips of your fingers. I would have loved to breed my rats, but after much deliberation I decided not to. One obvious reason was that I had no idea of Gus' background, and I would feel
so badly if the litter had serious health problems. Also, I didn't know the proposed father of the litter as well as I would have liked. Right there it sounded like something out of the "Do You Really Want To Breed?" pamphlet I'd read earlier. I had solid homes for at least 14 little rats, and sometimes told myself "well, I know about the hidden dangers, tumors, myco that can show up in petstore rats, but Gus is fine, and I know the people who own her brother and he's just fine too." But logic won out and I simply couldn't take the risk.
I still would really like to breed rats when I get older, out-of-school-with-a-steady-job older. But right now, I think I'm just too inexperienced. And what's more, the world doesn't really need 8-14 more rats (especially/mainly ones with questionable backgrounds) when there are already ones out there without homes. So in the meantime I will continue to read as much as I can about rats, especially their genetic traits. I may plan, or speculate, hope or wish, but for the time being I will not be breeding any rats.
Now here is where this post may be a little off-topic. It seems to me that this post is mainly just what you shouldn't do, and I don't always feel it completely helpful when only the negative side of an arguement is presented (ie "don't do this" but never saying what to do instead? if that makes any sense). I also think there would be benefits to saying what one would have to do to become a successful, ethical rat breeder. I imagine there would be many requirements that most people would not be able to fill. And, on the other hand, this might help me with knowing what exactly I might be getting myself into 10 years down the road

Thank you all for reading, and the best of luck.