Hi There
hope i didn't jump wrongly in the thread, since this is my first comment!!
any way,, in Islam the Custody is not only allowed, but also higly recommended, is to have any orphan, raise him/her , feed him/her like you children, educate him/her, and save him/her from lost.
in Addaption you change the name of the the orphan family, his father, his race...which is not accepted, because of changing the Derivation, and the regarding the humulation of controling any body's race.
hope i get answered the Q.
Thank you