Hermie Dwarf?

I have a Royal Dwarf that is going great guns, Good bud development and stem structure and where the nodes are on the main stem the calyxes have two hairs coming out of them. On the second node up from the bottom I noticed the hair had pulled back in so I plucked the calyx of and discovered a seed inside. I must insist that the plant is in full bud and has no male flowers or bananas. I have decided to retain the plant as it is by far the best of three i have (auto 2, lowrider 2 and Royal Dwarf).......I would really like to know peoples opinions and experiences with this. I have bought lots of pot that was great before and had just the occasional seed in it, could this be the case? Thanks guy, this site rocks....bless the sacred weed!