I've only seen the actual studies by Winn Feline Foundation and Cornell. What are these other studies, and where can I read the results?
I would definitely spay female cats and dogs before the first heat. Ideally after 3 months, to give more time for development, but that's sufficient to lower the risk of urinary incontinence in old age. I don't know how accurate the 0.5 - 1%, 8%, and 26% figures are, but I do believe there is some truth to them.
Physical "stunting" is weird. The main effect is closure of the joint plates, iirc. This results in slightly longer legs. I suppose this could be a concern if you're doing lots of certain hard physical exertion daily in certain environments, but it's not a concern for most "pets." S/N at 7 months, some plates already have closed, and at least one person out there is worried about this causing uneven proportions of bone lengths. Then you can wait 14 - 24 months, depending on breed and individual.
Some people are in favor of vasectomies and tubals for cats and dogs. Others are in favor of only spaying in the case of pyo or the like, and using management (as aqh88 did), but I agree, that won't happen so long as pets are treated the way they are now. People would think chainlink is secure enough, hah. And have no idea how to take their dog out on leash.
Sometimes my girls explore cautiously when brought back to their room. Even after being in the bedroom while their room is cleaned. Mostly they don't seem to have a problem. I'm lucky they have such good bounceback.
One problem I did encounter when trying to clicker train was separating them. They wouldn't be interested in food. Instead of letting them get used to a training area, I got lazy and gave up, especially with the cats around. Now that I can use the bedroom, though, I have fewer excuses
It really does make a difference.
It's not just about training cues, but the confidence, selfefficacy, problem-solving, which contributes to more defense against trauma and better bounceback. They're not so passive any more. They learn they can influence the world and what happens to them. That's a very powerful feeling for those who are used to being powerless and helpless. I haven't taught anything "useful" to one of my cats other than target training; the rest was for fun and to encourage her to be more playful, secure, and creative. She's usually very shy, anxious, easily startled, and slow to recover from stress. I'd never seen an animal tremble so much at the vet's. It really detracts from her quality of life.