..."we shouldn't do something until we know all of its consequences,"...
I think a strong argument can be made that in the case of genetic engineering we have great cause to be unremitting hard-asses about putting a concern for "consequences" above all else. Unintended consequences could quite conceivably bring about the end of all lifeforms on the planet.
No matter how many "years" researchers spend "growing generations of test crops" they cannot collapse eons of evolution into a few laboratory experiments. The risks they are taking are dauntingly real and have a direct impact on my life. I'll be damned if I am going to allow them to dismiss my concerns with a condescending pat on the head.
Learn how to make a neato beanie here. Put it on. Take a nap. The voices will stop - money back gaurantee.