Hi romdog11

I read a similar thread on this subject recently but can't seem to find it (damn that short term memory loss), however if I remember correctly, it is to do with two embryos growing in the same seed shell and fusing together. The prognosis isn't great for both to survive though, and I think some of the more experienced growers recommend 'nipping' the weaker looking one.

I'll try and find a link to the thread if nobody else chips in with wiser words.