The decision on consensual sex between teenagers is expected on Thursday.
The Teddy Bear Clinic and Resources Aimed at the Prevention of Child Abuse and Neglect brought a constitutional challenge against provisions of the act in the North Gauteng High Court in December 2010.
The matter was heard on April 23 and 24 last year.
A ruling was made against Justice Minister Jeff Radebe and the national director of public prosecutions on January 15 this year.
High court judge Pierre Rabie found the consensual sexual activities mentioned in the act were a wide range of acts that children engaging in ordinary sexual exploration, such as "French" kissing, would commonly perform.
He held that criminalisation would constitute an unjustified intrusion of control into the private sphere of children's personal relationships in a manner that would cause them severe harm.
The act, as it stands, has criminal implications for children between the ages of 12 and 16 who engage in consensual sexual activities.
Any individual who has knowledge of these acts, such as a parent, health worker, or teacher, is required by law to report the children or face prosecution.
The children, if found guilty, could have their names included on the national sex offenders register.
The Women's Legal Centre, a friend of the court, said the application was about protecting the rights of children to dignity, privacy and freedom, and access to health services. – Sapa