Re: Adopting a child - impact?
this is very good thinking on part of the couple but few things to consider:
as you mention they want to adopt only as an act of naiki, and already have 3 kids of their own, i am afraid they would be able to love the adopted kid the same way they love their own kids.
most couples who adopt a child do so because they are childless and have that craving to be a parent. they have the yearning for the child and when they adopt someone it is merely for the purpose to be a parent so they love the adopted child unconditionally like they would have loved their biological child. but in the case you quoted the purpose is different and if after adopting they cant love or treat the child the same way it will have a poor impact on the child.
on impact on biological kids and other family members, i have known 4 families who have adopted the kids and all of the relatives welcome this step. one couple was blessed with the baby of their own after 5 plus years of the adopted child and no one can tell that the two kids are not real siblings or that one is an adopted kid.