I was adopted by a stray kitten and had her spayed when she was old enough. A friend told me I had taken away her “choice” to reproduce. I asked her how many of my cat’s hypothetical offspring she was willing to adopt - there would be I guess an annual litter of four or more to choose from. Yeah no.
In the end I moved countries and gave the cat away. I would never have another one, nice as she was. There’s a family of voles living in my garden, half a dozen frogs in the pond and lots of birds visit my trees. I support them mainly by leaving them to go about their business.