The trouble with growing weed is there is a lot of bad info out there. Some of the old theory's on growing are about as helpful as Reefer Madness is to smoking it. The truth is weed is changing and improving all the time, so if you really want to know you should try it and see what happens. Personally I would not start with a seed from a hermi because you never know what will happen with them. Growing is a big investment in $, space and your time. For me I wont waste time over one seed when I can buy a good one for $10. By the time you know if it will hermi or not you have lost probably 8 weeks at the least and I some cash feeding it.  I have only had one plant hermi, it was a Northern Lights I tortured and it was still good smoke. I had 2 plants that made seeds and that was good smoke too. The seeds however were not.

Josh has good info above and you can pretty much take that to the bank, but I bet I can guess how he learned it.