Recent research focuses on comparing the prevalence of various medical problems between neutered pets of a certain breed entering veterinary facilities and their intact counterpart. When associations are found, researchers publish recommendations regarding when, if ever, pets should be neutered. The problem with this research is the difference in breeding, care and handling of neutered vs intact pets entering veterinary facilities. Based on a private conversation with an oncologist at the Ryan Animal Hospital, less than 10% of pets entering the facility are intact. These dogs are usually breeding, sporting or show dogs. They the best of the breed. They are exercised, fed and handled differently than the average house pet; many of whom were bred in puppy mills. Talk about comparing apples to oranges! If your main goal is to avoid heat cycles, breeding or unwanted behavior, a good time to neuter is 5-6 months of age. We prefer pets have completed their pediatric vaccines before neutering. Tis is generally at 4 months of age. Clients who are influenced by the research discussed above sometimes wait until pets are 1-5 years old or do not neuter at all. That choice is a gamble; quality research has shown mammary cancer is highly unlikely in dogs spayed prior to their first heat cycle. For shelter and rescue groups, pediatric spay/neuter (8 weeks of age) is the norm to prevent overpopulation by having the pets sterilized prior to adoption.