Cons
http://www.hhhumane.org/spay.html
http://www.cspca.ie/petcare/spayneuter.html
http://www.goodpooch.com/ISSUES/stopbreeding.htm - An interesting fact in this one. 65% of dogs come from "one time" breeding. Gee thanks.
http://www.geocities.com/jcrowe22/pe...opulation.html
http://dogs.about.com/library/weekly/aa090602a.htm

Pros
Hmm..no addies?? Well I can think of one reason off the top of my head -- cute puppies. Not a good reason? Of course it isn't, I can see cute puppies on my television.

And litterally, I couldn't find any pros to backyard breeding.