I've always thought alb x alb was a bad idea but you don't ever see anyone talking about it. Instead I see albinos for sale, and when they show pics of the parents, they are both albs. Leading me and probably others to believe it's fine.
It isn't as straightforward as that, unfortunately...a lot depends on the species, how the morph was developed, and the particular pairings. For example, with boas, for many years albino to albino pairings were discouraged because the Kahl line was plagued with eye issues. It was, and is, considered to be a defect caused by the amount of inbreeding done to establish and reproduce the morph. Now, like the wobble in the spider BP, it is basically felt to be a part of dealing with the morph (taking the bad with the good, if you will). I have heard numerous theories, and thoughts on how the eye defects can be prevented...but I haven't seen any valid evidence that any of them actually work. That is just one case, though, and there are many other species in which the albinos aren't problematic.
That said, the practice of inbreeding - while necessary, to a degree, in the proving and establishing a new morph - is too often deemed acceptable. How many times do you see people buying sibling pairs for breeding purposes, or talking about breeding babies back to parents? There simply isn't any reason - other than being lazy and/or cheap - to do that with established morphs.
This isn't exclusive to BPs, by any means...a lot of breeders perpetuate that by offering sibling pairs at a reduced price, or refusing to sell single females - I understand the practice from a business perspective, because they don't want to get stuck with a bunch of males they can't move; but hobbyists/breeders at all levels (IMO) should probably consider the messages they are sending both in practice and the information they give. I know, I know...some people don't have a lot of money to invest in their breeding projects - I'm not going to go there, except to say that there are plenty of options. Here are a few examples:
- Buy the female, and wait 12-18 months before purchasing a male. Prices will typically have dropped so you can save some money (often more than you would have saved by buying the sibling pair).
- If you are working with recessive traits, prices fall quickly on male hets. You might not get as many of your morph; but if you're on a budget, it makes sense. When it comes right down to it two years down the road, you can often purchase a visual male for what you paid for your original het female.
- Rather than breeding hets back to parents or siblings (again, talking about established morphs), do some networking and trade some of your babies for unrelated stock.
- If you find your dream snake, and you can't seem to get them except in pairs...consider buying a pair from two different breeders. Keep the male from one pair, and the female from the other; and you'll have an unrelated pair to sell. (Don't keep both pairs to make a breeding group - the whole reason for doing this is genetic diversity)