Within 20 years gaian thinking probably won't seem so silly - we are part of a macro organism.
edit: replaced with Wikipedia page which has more detail.
Which is also my counter-criticism of the idea that this idea destroys the objection to GMO... the natural mechanisms still co-evolved with us ("us" being the whole biosphere here). It is mathematically reasonable to be concerned that fully artificial genetic manipulation is of a different kind, and not merely of a different quantity. (Even ignoring that in the latter case, sufficient quantity takes on a quality of its own.)
Generally I've been pretty positive on GMO food but I have to admit that the mathematical argument against it has a certain potency, when you understand the mathematics of evolution. There is a significant qualitative difference between coevolved mechanisms and artificial mechanisms that ignore that history. I'm still not convinced that our current skills are really great enough to produce some sort of disaster, but that's a debate point with an expiration date on it.