Here's the main reason I'm ambivalent about anti-vivisectionist petitions - if the drug companies don't test their products on innocent animals, would we still have the medical treatments we have today?
The genes I've ended up with have ensured that I get a fair bit of experience in the use of medication (for my allergies, for instance). And in the last couple of days I've been grateful for the painkillers, anti-inflammatories and muscle-relaxants that have made my back strain that much less torturous. I'm now at the point where I can sit and stand with only moderate amounts of pain. So I'd be a hypocrite to voice opposition to testing on animals, wouldn't I?
If only scientists could test on violent criminals instead.