I have always found it bizarre that people profess their love for their pets, treating them in many respects better than fellow humans, yet castrate these beloved animals as a matter of course. In my view, castration is a vile mutilation and an extreme violation of a creature's dignity. An animal that requires castration for the purposes of taming perhaps should not be kept as a pet in the first place. Clearly there is a need to control population. Less invasive and potentially reversible measures such as vasectomies are more humane but rarely used alternatives.
Once again, technology comes to our rescue, allowing us to be more civilised. A new drug has been released in Australia which limits both sperm and testosterone production for several months thus fulfilling the targeted aspects of castration whilst preserving dignity and reversibility. There is an argument to be made for administering this to some people.