Dr. McCann has been working in the field of Child Abuse and Neglect for the past thirty years. Following his graduation from the University of Michigan's Medical school, Dr. McCann spent two years in the Navy as the base pediatrician in Annapolis, Maryland. Following his discharge he entered into a private practice in Seattle Washington. From there he joined the faculty of the University of Washington and was appointed Chief of Pediatrics at Harborview Medical Center, a University affiliated hospital.

It was there that Dr. McCann first became interested in the issue of child abuse and neglect. In the early seventy's, through the efforts of his colleague, Dr. Shirley Anderson, one of the first child and adolescent sexual abuse evaluation programs was begun. 

Dr. McCann took that interest with him when he and his wife moved to Fresno, California to help develop a Primary Care Training Program for the University of California, San Francisco. Recognizing that very little was known about the "normal" genital findings of the prepubertal female, he and his colleagues developed a research project aimed at answering many of those questions. In addition, they followed up with articles on the healing of genital injuries, the use of the colposcope in the evaluation of the prepubertal and adolescent girl suspected of having been sexually abused or molested and the application of the "multi-method" examination approach to the evaluation of these subjects.

Dr. McCann spent the last twelve years of his medical career as the Medical Director of the Child Protection Center at University of California Davis, Medical Center. There he continued his research in the healing process of anal/genital injuries as well as chairing the American Professional Society on the Abuse of Children (APSAC) committee that developed the Practice Guidelines: Descriptive Terminology in Child Sexual Abuse Medical Evaluations. He was also instrumental in the development of the child and adolescent sexual abuse reporting forms used throughout the State of California.

Dr. McCann has won numerous awards including the 2001 American Academy of Pediatrics section on child abuse and neglect award for Outstanding Service to Maltreated Children.