In order for the plant to begin growing seeds there had to have been pollen present, either from a hermie flower/banana, a male plant (neither is likely from your description), or possibly pollen transfered from your clothing to your plants from another grow room. Either way, whats done is done. The good news is that when pollen gets on the pistils of the plant, it only pollenates that area of the plant, not the whole thing. So you may only have a few buds or a branch pollentated.
Keep a close eye on your plants for pollen sacks. They are sneaky as hell.

Hope this helps.

Grow on...