I just called the College Board and was told that as of June this year, due to Federal regulation, children under 13 are no longer allowed to write the SAT. Does anyone know why?

I was hoping to register DS11 for the SAT to qualify for CTY/DYS. I was partial to the SAT because it is widely recognized (which will help me advocate for him with the local school district), and that DS is comfortable with the format. Which other tests would be most similar to the SAT in these regards?