There will always be variation between people, but children can't consent to just procedures because they can't cognitively understand what the consequences will be (as in not understanding the gravity of them). Here's Piaget's stages of cognitive development, which are well-worth looking over if you haven't heard it 10,000 times. Haha
![[Image: SigBarSping_zpscd7e35e1.png]](https://images.weserv.nl/?url=i169.photobucket.com%2Falbums%2Fu224%2FUchiha_Kina%2FTags%2FSigBarSping_zpscd7e35e1.png)