can a biological child from a good home have RAD?

Yes, bio kids from a "good" home can be RAD. RAD can stem from a mother who didn't feel attached to the baby while in the wound or after the birth (perhaps due to depression, stress or a whole slew of other reasons). Babies who had to spend time in the hospital following birth (preemies, heart issue, etc.) can have RAD. Babies who were very collicky have been shown to have RAD (cried so much they were unable to form early attachment). Early trauma can lead to RAD, even if it had nothing to do with the bio parents. Lots of circumstances make RAD a possibility in bio kids. It's not an adoption disease. (A fellow blogger recently wrote about this. Check it out at: [url=http://puddingwithoutmeat.blogspot.com/2011/09/rad-is-not-adoption-disease.html]Pudding. Without Meat.: RAD is not an 'adoption disease'[/url])