All of us in agriculture have. They've been used for years now.
I'll expand a bit on what Answerman said. There is a sort of bacteria,Bacillus thurengiensis, or BT which has been for years a life saver. The older people here remember when we often got worms in our ears of corn. Caterpillars are expensive!! Take fruits and nuts. You can't hardly sell apples if the customer gets a half of a worm after a bite. But you could spray this bacteria on your crops, and it would only target caterpillars. Not the good bugs, which is good for stewardship, and you don't have to wait much time after spraying before you harvest, because it doesn't hurt humans or farm animals to eat it. Not like dangerous chemicals, which can require over a month before you can legally harvest, due to it's danger to us.
So, someone gets a bright idea. Take the genes that do the actual killing of the caterpillars from BT and splice them into crops. Take corn. If you could cause caterpillars to die just by eating corn just think about how much gas, pesticides, labor etc.. you can save. Good for everyone, right? I remember my roommate in Uni, who's from a big walnut growing family. Think about how big walnuts are. Think about the expenses of spraying every inch of an orchard of trees thirty feet tall! He used to dream about splicing those genes into walnut trees.
And the same for tomatoes. I did a trial for my company for long shell life tomatoes. Imagine a tomato that will keep for weeks!!! You just take a gene from a sheep, splice it in, and there you have it.
So, now to ethics. For a theonomist, it's a no brainer. You're mixing things you're not supposed to mix. If you can't mix something so close as a horse and donkey, how much less a tomato and a sheep.
We can develop another couple ethical points as well, and I'll start with something that came up in a conversation with one of my landscape suppliers, a guy who has several nurseries.
So, we have corn. Really valuable, right? Where do you go if you want to breed something like disease resistance into corn? Or other useful traits? Like high levels of lysine or other nutritional benefits, getting corn to grow in difficult climates, etc..
Where you go its to where corn came from. To the huge genetic pool in Central America where corn came from. You go around and collect all sorts of samples of corn from villages, corn like grasses and so forth and start looking for genes. But what happens to that gene pool when some farmers get this genetically modified corn to grow? Corn is open pollinated. Before you know it (and my friend said it's in the process) that wonderful gene pool is polluted by the pollen of this Frankenstein. I don't think I have to draw this out further.
Now another (since I'm on a roll). So, this pollen causes this gene to get into other grass family species. Say it's a weed that naturally is kept under control by (drum roll) caterpillars. What type of advantage are we giving to something that will become an enemy to us in the future? Super weeds!
There's quite a bit more we can draw out. I frankly doubt that that gene will do anything to us, Answerman (although if you've seen research, I'll defer to you). We've been eating this stuff as a minute pesticide residue for years. It surely can't get into our cells. I can't see how it would build up in us (although again, I'm teachable). But there are SOOOO many other ways that this technology can do some major league messing around with things I'm in favor of stopping it right away.
You know, I've noticed that whenever someone comes up with an idea of removing the Sweat from our Brows in agriculture, it comes back to bite us. I'm all for saving effort, efficiency and the rest, but creating new life forms isn't the way to go, in my humble opinion.
