This trial aims to investigate the effects of a single injection of stem cells from the bone marrow in children with diagnosed Autism. The trial is being conducted by the Hospital Universario in Monterrey and proposes to enrol 30 subjects between November 2012 and November 2013. All participants will receive an injection of G-CSF to release stem cells from the bone marrow into the circulation. The stem cells will then be collected from the child's blood. Half the participants will injected with the stem cells in the first six months (initial experimental group), while the other half will not have the cells injected until the stage of the second six months (initially a control group). The cells will be injected into the fluid that surrounds the spinal cord (intrathecal injection). Participants will be monitored for complications following the injection and changes in clinical condition.