Just what it says the seeds have been modified to be resistant to weed killer or to fungus or to need less water or what ever they felt they needed to improve for soya.
ISMU that a lot of soya is American and it the norm over there.
Meaning it is resistant to Roundup (glyphosate) which is a herbicide.
I personally wouldn't be worried about it myself.
ETS: we work for/with Monsanto to test for the modified gene in their GM soy but I can't remember exactly which one it is or how it is modified. If I could I wouldn't be allowed to tell you anyway. Like I say, I don't think GM crops are remotely scary in of themselves. Monsanto on the other hand, well, I'm not getting involved in the debate about them