if its just a few and youre pretty close to finishing, then id say go ahead and let them finish. ive had a few instances where a couple bananas popped out and it only made about 5 seeds out of an ounce. youll be fine to let them finish out. if youre extra paranoid and dont want any seeds at all you could take some tweezers and pluck them out. also a little tidbit aboutthe bananas, im pretty sure if you use pollen from them to pollinate something there will be a higher chance of it being female.