article_snippet.sent: More than 13,000 twins aged nine to 16 took part in the research (stock image shown)
article_snippet.sent: Psychologists from Goldsmiths University of London, and Ohio State University in the US studied more than 13,000 twins aged nine to 16 from six countries, including the UK, Canada, Japan, Germany, Russia and the US.
highlights_snippet.sent: More than 13,000 twins aged nine to 16 took part in the research .
  