Background: The aim was to investigate the role of measured intellectual function in framing parents as 'unfit' in child custody deprivation cases. Method: Grounded theory was used to analyse a national sample of custody deprivation cases in Iceland 2002-2014. Results: The terminology used to evaluate and describe the intellectual and developmental status of parents in child deprivation custody cases served as a device to define and shape the 'unfit parent'. Intellect itself, whether as low, average or even above average at times acts as a master narrative which informs and explains all manner of perceived parental deficiencies. Conclusion: The intellectual and developmental status served as a yardstick of identifying, understanding and interpreting the unfit parent. As a tool to achieve an end, parents were framed in language and culture using underlying belief set to make sense of events and issues.