Over the last decade, it has become apparent that performing a gonadectomy (spaying or neutering) has unanticipated health implications. Specifically, gonadectomies and the age at which they are performed have been linked to the incidence of many cancers, orthopedic conditions, other medical conditions, and behavioural issues.

Read more of this article at iaabcjournal.org -spay-and-neuter-surgery-effects-on-dogs/

Very interesting read