Foreskin retraction (natural history)

• glans penis and prepuce have a common epithelium which gradually separates and keratinises.
  
  
• time of completion of separation occurs any time from late gestation to teens.
  
  
• in 4% of newborn boys there can be complete retraction of the prepuce.
  
  
• full retraction is not possible in up to 60% of 6-9 year olds due to remnants of the common epithelium.
• by the age of 16-17 years, approximately 95% of the boys will have a retractable foreskin (1)
  
  
• smegma forms in the preputial space as the child matures in 1% of 6-7 year olds and 8% of 16-17 year olds. It is sensible to direct boys from about the age of 7 years to gently retract the foreskin during bathing to wash the glans and the preputial space, and then to replace the foreskin.

Reference:

Statement from the British Association of Paediatric Urologists on behalf of the British Association of Paediatric Surgeons and The Association of Paediatric Anaesthetists. Management of foreskin conditions