I have been wondering what is meant by the SPCA (and by all rescue groups) by pre-adoption sterilization of all animals.

Do we mean 8 week old kittens, because AAS doesn't do that. Nor puppies. I am not comfortable with pediatric sterilization as there is still controversy over the procedure. So I don't hold the SPCA to that standard.

AAS waits until kittens are 5 months and puppies 6 months, but we can't insist that should be everyone's standard. Also, we make sure that the animal does get sterilized by choosing homes carefully and by checking back. Our careful selection of homes means that not one person has ever reused to get their pet sterilized. (Careful selection of homes also distinguishes between a real adoption and a sale.)

Does the SPCA's announcement mean every animal will be pre-sterilized, or just every animal that is old enough? And what is that age?

I have never heard of any animal welfare organization that adopts out intact adult or even juvenile animals.... except for the SPCA of course.

But nor have I heard of an organization that does pediatric sterilization on all kittens and pups. I'd be interested in knowing what other groups' policies are.