RE: incest myths

Do you know any websites that talk more about this? I've always been sceptical about the idea that when two people who are cousins have a child it invariably comes out with two heads, but I haven't been able to find anything that talks more about it.

You have to understand genetics a bit to see where the problems like this arise (and they do.) The thing about incest isn't that just because people are related they will cause problems. First you need to understand that everybody has recessive genes for some faulty issue or other, but there is often a low chance of problems manifesting if there is enough genetic diversity. The problem with incest is that you might have two people who have recessive genes for the same problems (since they are of the same stock), meaning they have a much higher chance of manifesting the problem in their offspring. And the more you inbreed, the higher the chance becomes of it manifesting. Also, the closer relation the breeders are to each other, the higher the chance of negative recessive traits manifesting (to say nothing of negative dominant traits manifesting.)