Twin Research and Human Genetics (Journal)
- Associate and Contributing Editor (1999-present)
- Editorial Board
Board of Scientists, Ethospace
- Toulouse, France, (2015 - present)
Human Behavior and Evolution Society
- Member-at-large (2013-present)
- Chair: Committee, Lifetime Achievement Award (2015)
- Member: Committee, Early Career Award (2018)
International Society for Human Ethology
- Trustee (2014 - present)
- Associate Editor, Human Ethology Bulletin (2016 – present)
Hungarian Twin Registry
- Scientific Advisory Board (2015-present)
American Psychological Association
- Division 1: Member-at-Large (elected 2009)
- Division 1: Co-Chair, Programs (2007 – present)
- Member-at-Large (2009 – present)
Creativity Post
- Twins: Blog (2012 – present)
Psychology Today
- DoubleTalk: Blog (2008 – present)
British Broadcasting Corporation
- Consultant (2002)
- Twinstuff Outreach (2002-present).
International Society for Twin Studies
- Advisory Board (2001 – 2004)
Behavior Genetics Journal
- Editorial Advisory Board (1999-present)
TWINS Magazine:
- Contributing Editor--Research (1984-1998)
- Editorial Advisory Board (1985-present)
- Editorial Consultant (1995-1998)
- Introduction to The Twinship Sourcebook (1992)
Across Species Comparison of Psychopathology
- Advisory Committee: Plenary Session (1995)
Center for Loss in Multiple Birth. Palmer, Alaska
- Advisory Board (1992-present)
Twins Foundation. Providence, RI
- Advisory Board (1993-present)