it's been really interesting reading all of this but i can see why the owners on this site with littermate pups might be getting a bit defensive. i hope they don't start to feel that they had better not ask for help with future problems as a result, for fear of being slam dunked with the littermate issue.
if people who have chosen to buy littermates do it fully aware of the risks and prepared to work hard to ensure that their dogs lead a happy and healthy life then in my opinion that's got to be better for the pups than the lives that many poor dogs end up leading in this country. if things go wrong down the line, then possibly one will need rehoming. this is obviously not what anyone wants but i'm sure there are plenty of dogs that need rehoming for other reasons, such as a death or illness in the family or other changes in circumstances. if i got run over tomorrow my OH, who works long hours, would find it very hard to keep barkley. he's lucky that he has plenty of family around that would try to help but he still might decide that it was better for barkley to go to a new family with a new 'mum' who can be with him 24-7. this is a gamble that we have taken on barkley's happiness, and not one that we took lightly, yet we still feel we are right to have got him.
i've probably gone completely off track, and i'm sorry if i've stepped out of line, but i'm just trying to say that everyone has a different opinion on this and i just wanted to make sure that some people didn't start to feel that theirs was categorically wrong, when it might not actually be for them or their dogs.