XYY

• What is XYY Syndrome?

  A genetic condition that occurs when a male has an extra Y chromosome
• How common is XYY syndrome?

  1 in 1,000 male births.
• Is XYY syndrome inherited or a random occurrence?

  Random occurence
• Do individuals with XYY grow faster and taller or slower and smaller?

  faster and taller- on average 7cm taller
• What % of boys with XYY have delayed speech development?

  50%
• How many points lower is their IQ compared to their siblings?

  10 - 15
• Do they find it harder or easier to concentrate?

  harder
• Are they more or less impulsive?

  more
• Are they more or less physically active?

  more
• What did Jacobs find in support of XYY syndrome as an explanation of crime?

  males with XYY syndrome were over-represented in prisons

  15 XYY males per 1000 prisoners compared to 1 in 1000 in normal population
• What does XYY syndrome as an explanation of crime not consider?

  female crime
• What did Re and Birkhoff find that does not support XYY syndrome as an explanation of crime?

  conducted a literature review of articles from the last 50 years and concluded that XYY males were not necessarily more likely to become anti-social or aggressive
• How is XYY syndrome as an explanation of crime useful?

  if we know that XYY males are more active and easily distracted then we can put in place strategies to help them at school and reduce antisocial behaviour.