Absolutely, which is why any surgery should NOT be taken lightly. Google "botched spay surgery" and you will find groups that are very opposed to this mutilation for this reason as well. Personally, I find that while there IS risk, the actual complication rate is very low, and the reward outweighs it on the pros/cons. That is my opinion though, and I do respect people that simply do not wish to molest ANY part of a cat's natural anatomy, as long as they are willing to deal with the repurcussions for the life of the kitty.
There are very obvious behavioral changes observed in the animal. They are beneficial ones from my standpoint, which is why I would not want an intact feline. My coworker's cats that I had mentioned, which I almost adopted myself since he has too many (seven), still "scratch" and behave as would any cat, and no, I cannot see any difference in gate nor agility (if there are youtube videos demonstrating the difference I'd be happy to add that into the cons list in my recommendation to others). It is unnecessary elective surgery though, risky for the cat were it ever to escape (Wesley already has TWICE now, the little adventurer monkey hehehe), and just isn't needed as my munchkins are well behaved (mostly).
