The United States Embassy has a statement on adopting children from Morocco:
If you wish to adopt a child abroad, and you are in the United States, contact the Bureau of Citizenship and Immigration Service office that has jurisdiction over your place of residence. Please be advised that securing custody of Moroccan orphans for immigration is extremely difficult as adoption is essentially illegal in Morocco.
I do not know the full story, but my understanding is that the prohibition stems from a desire that Muslim children not be adopted by non-Muslims and so lost to the faith. After all, the King of Morocco is still the Emir Al Moulmenin (Commander of the Faithful).