Pre-Mature Pre-Flowering?

So upon inspecting a batch of planted seedlings we discovered that there were two plants that had full mature male sex organs. The odd part is that these plants are 1 week old in vegetation (excluding the 21 nursery days). It has one set of leaves, working on it's triple leaf sets. The plants is far two young to be expressing sex in my experience. Has anyone ever heard of anything like this? I am running a constant high ppm of co2 (900-1200) and I am wondering if the abundance of co2 is causing this. I know it is not the particular pre-flowering traits of the strain itself because I have been using the particular strain for some time without this behavior. Could the problem be some flaw on the environmental side of the grow? Please help.