Madonna will be granted permanent custody of her adopted son five months earlier than she thought.The 'Hung Up' singer is set to appear before Malawi's high court next month for a review of her temporary adoption order of her two-year-old boy, David Banda.It is expected the hearing - which was originally planned for next April - will make Madonna and husband Guy Ritchie David's legal parents.However, human rights campaigners claim the couple - who adopted David from Malawi last October - have received special treatment.Lawyer Justin Dzoni insists Madonna should have had at least 18 months of temporary guardianship so her suitability as a parent could be properly judged.He added: "If this is true it would appear the rules have been bent."Last month, it was revealed Madonna would be allowed to keep David after she was visited by the head of Malawi's Social Services, Simon Chisale.Chisale spent three days with Madonna, Guy and her two other children, Lourdes, 10, and seven-year-old Rocco, at the family's London mansion.Chisale - who was assessing the couple's suitability to adopt David - was particularly impressed with the measures the family had taken to make David feel at home.He revealed that Madonna and Lourdes speak to David in his native language, Chichewa, and said the little boy had bonded very well with his new family.