Are the seeds you buy from seed banks considered to be stable strains or Im I still confused??
It depends on the seed bank, like homebrewer said. Again, this is why some banks are more reputable than others. Some banks are selling F1 generation seeds and calling it whatever another seed bank has created as a stabilized strain. This is very common; F1 and F2 seeds being sold and just naming it after the targeted strain because the parent strains are known. Also, they don't normally disclose what level generation the seeds are. They just sell the seed, and unknowing customers buy the name. True enough, it may have come from the same strain parent plants as the better know and famous strain, but it's not the "true" stabilized strain that a reputable breader put the time into to get the reputation it has.
That is one reason for example, the parents of Sensi Seeds' Jack Herer are unknown. Many other newer strains, it's parents are known and are easily copied and resold by other banks... usually F1 or F2 generations.
Don't fret. Older strains for the most part have been distributed for so long, now if you buy say, Northern Lights from 90% of the larger seed banks, you're getting the real stabilized strain. This is true for the most popular and older strains. But some strains have become popular, and are NOT from the original, true stabilized genetics.
I'm not going to go into which strains are heavily copied... but I'll say this. When buying seed, do your homework on where the strain came from if you're really concerned about its genertics. If you just wanna grow some fire-assed weed, any seed will do as a place to start. So basically, get your seeds from the bank that created the strain if you specifically want to mix say Jack Herer and Blueberry. But if you just smoked some good shit last night, and had some good shit at a buddies house, it doesn't matter if those plants are stabilized or not. Sure, it helps. But you're creating something new anyway. It's going to take some time.
I'm ranting now... sorry.