what you wanna do is just grow the seeds that you do have, until they are ready to clone. when they are ready to clone, you pull clones from each of the plants and throw said clones directly to bloom. after about 2 weeks the flowers will start and you will know which palnts are male and which are female. Another way to do it is wait until about week 3 or 4 of veg, when they can handle a nute blast, and hit them with a high potassium fertilizer. Palm Ash works good, 0-0-30. that will help it to preflower making distinction a little easier. Those are two ways to tell. Ive used the first method very successfully and just found out about the 2nd and have just been waiting for a need to try it. And as far as feminized seeds go, most of those are made from hermy plants and as such have a higher tendency to be herms. However, high end strains from seedbanks tend to have rockin genetics and so you dont have to worry much with those. But seeds from just anyone that says they are feminized most likely do not have such awesome genetics. BUt again, there is still hope. With those types of seeds, you can get somethin like Dutchmaster Reverse(or HCO Bushmaster) and a good wetting agent(they recommend Saturator, but any other brand will work, as will castille soap, Saturator does work best though) and spray that on them once you put it to bloom and then again ten days later and again tendays after that and it will help to CONTROL the herm. If its a really unstable seed(because some seeds will be stronger) you will still need to cut it down.