Two Plants One Bean?

i had purchased some G13 labs pineapple express feminized seed, a while back and finally decided to pop it. the bean was germinated for 2 days until the tap root showed. it was then put into a 16oz plastic cup of soil for 2 days when something weird happened...
out of the soil 2 plants started emerging...one looked like all the other pictures of pineapple express that ive seen while the other plant had 2 rounded leaves. i separated the the rounded leafed plant into another in a separate 16 oz plastic cup, with holes poked in the bottom for drainage.
i put cling rap over the top of the plants to raise humidity, until the seedlings were touching the cling rap 2 days later. both plants show extreme vigor and are covered with thousands of tiny hairs. the plant with the rounded leaves actually doesnt look like its forming a second set of leaves, but a third rounded leaf thats folded in half right now. this makes me wonder if its not a polyploid but since im such a noob its hard for me to tell so early.

what im wondering is if this is a rare phenomenon, or if in fact someone else has had this same scenario before?
i will upload a photo as soon as i find my camera cable or get to a computer with an sd slot.

i've seen it about maybe five or so times since i've been here on riu.. my one friend, that is how i started talking to her on here, she had a grow called got twins.. same thing happened to her.. i think the one plant died after a couple of weeks though.. i've seen a couple of others have the same thing since then though..

thank you for the quick response. as promised here is a pic.
the twins are the front left and the front middle.

Hi there,

My last grow i had a WW bean that popped 2 tap roots (paper towel method) Planted and 2 plants came up. after about a week I re-potted them up in seperate containers and although one was stronger than the other, they both made it to harvest. Good luck.

it happens, quite common actually, sometimes this can net you poor results, the seedlings can end up being sort of like half of a plant genetically in turn you get half sized buds, leaves, stems, everything and overall it is subpar results - other times everything works out just fine - I find the times it works out normally is when you have one really strong one and one weak one instead of two alike ones. You should probably separate them or kill off the smaller one that is what I used to do, or if your not in to gambling and possibly wasting like 3 months of your life just kill both of them. Ever since I experienced the genetic halfling type of mutation the second time as a result of growing one these out I quit letting these ones live as its not worth space & time in my room.

so in summary:
1) its not rare
2) It can be a bad sign
3) just kill it.

I had twins, they both survived however the yeilds were a lot lower than the singles. The strain was sweet speed devil. It was good fun though....

thank you all for the responses. well this is my 2nd run so i dont know if i want to ditch them, i might just finish them out just for the experience. i planed on moving them outside once they got too big for that case which will probably be in a month. so the space isnt an issue for me it actually trying to keep them alive and healthy till they go outside.
the plants in that case from top, left to right are: grape god, WW, grape god. the ones on the bottom, from left to right: pineapple express twin 1, pineapple twin 2, and lemon skunk.

are there any training methods that i can perform to the plant that can help to increase the yield a bit more? i was thinking about an outdoor ScrOG being the best bet for increased yield, without that much work. please correct me if you think of a different method that would be easier to be established in a Gorilla Grow?

anybody disagree or agree on the ScrOG? any other training that would help promote bigger yields?

I just started the big from BCBD they all sprouted and two of the plants are twins one has two virtually identical healthy looking sprouts and the other has one normal and a wee runt next to it I transplanted them and haven't decided what to do with them my instincts tell me to kill em but I am curious to see what they do?? any thoughts or words of wisdom from some of the ganja gurus out there??