The 4th International Network of Twin Registries (INTR) Consortium Meeting took place in Osaka, Japan, September 28–29, 2015. The venue was the Osaka Medical Center for Medical Innovation and Translational Research. An overview of presentations and other activities is provided. Next, 1930s research on familial fraternal twinning, preference for masculine faces, physical aggression and epigenetics, and a prenatal education program for parents of multiples are described. Current twin-related events include the 2016 Guinness Book of World Records (GWR), the oldest living male twins, newly reunited twins, the birth of panda twins and a controversial twin-based website.

We are sad to announce the passing of Andrew E. Czeizel on August 10, 2015, at the age of 80, after a long-lasting illness.