Have you ever adopted a baby ,?
No i am not a fan of you assuming the  the parenting of another person's biological  child
So adaption dates back to what era?
I think Modern systems of adoption arose in the  20th century and tends to be governed by comprehensive statutes and regulations.
Any international laws on adoption?
Of course yes. but the prospective adoptive parents must meet the legal adoption requirements of their country of residence and those of the country whose nationality the child holds
Would you regard an adopted child as equal as yours?
Like i said i am not a fan of adoption or assuming  the parenting of another child