The guardian/child relationship has specific rules under Islamic law, which render the relationship a bit different than what is common adoption practice today. The Islamic term for what is commonly called adoption is
kafala, which comes from a word that means "to feed." In essence, it describes more of a foster-parent relationship. Some of the rules in Islam surrounding this relationship:
- An adopted child retains his or her own biological family name (surname) and does not change his or her name to match that of the adoptive family.
- An adopted child inherits from his or her biological parents, not automatically from the adoptive parents.
- When the child is grown, members of the adoptive family are not considered blood relatives, and are therefore not muhrim to him or her. "Muhrim" refers to a specific legal relationship that regulates marriage and other aspects of life. Essentially, members of the adoptive family would be permissible as possible marriage partners, and rules of modesty exist between the grown child and adoptive family members of the opposite sex.
- If the child is provided with property/wealth from the biological family, adoptive parents are commanded to take care and not intermingle that property/wealth with their own. They serve merely as trustees.
These Islamic rules emphasize to the adoptive family that they are not taking the place of the biological family -- they are trustees and caretakers of
someone else's child. Their role is very clearly defined, but nevertheless very valued and important.
It is also important to note that in Islam, the extended family network is vast and very strong. It is rare for a child to be completely orphaned, without a single family member to care for him or her. Islam places a great emphasis on the ties of kinship -- a completely abandoned child is practically unheard of. Islamic law would place an emphasis on locating a relative to care for the child, before allowing someone outside of the family, much less the community or country, to adopt and remove the child from his or her familial, cultural, and religious roots. This is especially important during times of war, famine, or economic crisis -- when families may be temporarily uprooted or divided.
"Did He not find you an orphan and give you shelter? And He found you wandering, and He gave you guidance. And He found you in need, and made you independent. Therefore, treat not the orphan with harshness, nor drive away a petitioner (unheard). But the bounty of the Lord - rehearse and proclaim!" (Qur'an 93:6-11)
http://islam.about.com/cs/parenting/a/adoption.htm