Alright you see whatever strain it is here and there that's supposedly g13 x ..whatever. BULLSHIT. If you had a plant that was actually g13, actually the dopest phattest bestest weed ever, would you cross it with ANYTHING? hellllllllllllll no. Anyway I could be wrong here, just a random thought.
umm... you would cross it to make seeds dude. cuz pure g13 only exists as a clone so far, you have to cross it with something that can produce seeds.
oh............. I just figured you could clone a male and a female, a female clone would still be a female, so.. nevermind then.