Classic, Provocative and/or Influential: A Twin Study Sampler/Twin Research Reviews: Twin Pregnancies With and Without Polycystic Ovary Syndrome; Ectopic Twin Pregnancy; Sex Differences in Cognition; Maternal Cardiac Hemodynamics/Newsworthy: President Obama's Portrait Artist; Winkelvoss Twins Update; Triplet Models; 'Meet Your Twin'.

Selected twin research papers that are classic, provocative, and/or influential are surveyed. Many papers meet these criteria, so those chosen reflect the opinion of the author. Reviews of recent research on twin pregnancies with and without polycystic ovary syndrome, ectopic pregnancy, sex differences in cognition and maternal cardiac hemodynamics follow. Newsworthy twin-based items, including President Obama's portrait artist, the financial activities of the Winkelvoss twins, a set of triplet fashion models and the experience of seeing oneself in a painting, are summarized. [ABSTRACT FROM AUTHOR]