A lower administrative court ruled against the plaintiffs on April 29, prohibiting them from restoring their Christian identities on their national identification cards.
Egypt's Supreme Administrative Court accepted their appeal Monday and referred the case to a related committee that will make the final ruling, said Mamdouh Naklah, a lawyer for 12 of the plaintiffs.
"This is a good step forward," Nakhlah told The Associated Press. "We hope the ruling will be positive."
Court officials said government lawyers objected to Judge Essam Eddin Abdel-Aziz's decision to accept the appeal, arguing the initial verdict issued in April was in line with the principles of Islamic Sharia law.
While Islam accepts Christianity as a fellow monotheistic religion, Sharia law considers conversion to any religion apostasy, which some conservative Muslims say is punishable by death.
The government attorneys planned to dispute the judge's decision, said the officials, speaking on condition of anonymity because they were not authorized to speak to the media.
But the director of the Egyptian Initiative for Personal Rights expressed support for the judge's decision to accept the appeal.
"Today's ruling is undoubtedly a step in the right direction," said Hossam Bahgat. "We are hopeful and optimistic that the Supreme Administrative Court will eventually uphold the principles of religious freedom and non-discrimination, both of which are guaranteed under the Constitution and international law."
In the initial ruling, the lower court accused the plaintiffs of "manipulation" for changing from one religion to another.
But the government allows Christians to convert to Islam without difficulty. One of the reasons Egyptian Copts convert to Islam is to obtain a divorce, which is generally prohibited by their church.
Coptic Christians are about 10 percent of Egypt's 76 million population and generally live in peace with the Sunni Muslim majority, though occasional sectarian clashes occur.
Some of the plaintiffs are children who automatically became Muslim when their parents converted. All have declared they want to return to the Christian faith.
Last year, the Supreme Administrative Court overruled a ruling to recognize the right of Egyptian Bahais to state their religion on official documents.