Recollections and Reflections on the Reimer Twin Case in Canada: Interview with Dr H. Keith Sigmundson/Tribute and Twin Research Review: Remembering John L. Hopper; Nonhuman Primate Twinning/Human Interest: The Accidental Twins film; Different Looking Identical Twin Newborns.

Dr H. Keith Sigmundson co-authored a seminal article (with the late Dr Milton Diamond) that revealed the truth about a highly controversial twin case. Specifically, the genitals of an infant male monozygotic twin were accidentally destroyed during a medical procedure performed to alleviate his difficult urination. The child's parents were advised to physically and psychologically transform their twin son into a girl. Occasional reports about the case indicated that the plan was successful, but some members of the medical community were doubtful. An interview with Dr H. Keith Sigmundson, for the purpose of obtaining his unique perspective on this case, is presented. The interview is followed by a tribute to our late twin research colleague, Dr John L. Hopper, of Melbourne, Australia. A review of research on nonhuman primate twinning, an overview of a 2024 documentary film, The Accidental Twins, and a story of different looking identical twin newborns are also provided.