Unrelated ART Twins / Tribute: Dr Robert Derom / Twin Research Reviews: Transfusion Syndrome; Discordant MZ-Twin Method / Matched Talents: Tennis Twins: (Mike and Bob Bryan; Sonchai and Sonchat Ratiwatana); Television Twins: (Ellen and Lynda Kahn)

Aunique case of artificially conceived twins is described. The infants involved are unrelated to one another, as well as to the mother who carried them. The question of whether these individuals meet scientific criteria for being twins is considered, as is the issue of whether their parents are really parents of twins. Next, the International Society for Twin Studies acknowledges the life and work of its late esteemed colleague, Dr Robert Derom. His professional accomplishments on behalf of twins and twin research will be remembered, as will his helpfulness and generosity to fellow investigators. This tribute to Dr Derom is followed by reviews of new research on the pathophysiology of the twin transfusion syndrome and the use of discordant MZ twins (co-twin control) in behavioral research. The final section provides a review of the athletic talents of two sets of MZ twin tennis players, and the creative skills of a set of MZ twin designers.