Prosecutors believe Kasab is 21 years old, but Kasab's court-appointed defense attorney believes he is younger than 18 and should be tried as a juvenile.
Kasab's charges include "waging war" on India and, if convicted, he faces the death penalty. But if he is 18 or younger, his case goes to juvenile court where he can only receive a maximum punishment of three years in prison.
"He has no birth certificate or the required documentation," Kasab's lawyer, Abbas Kazmi, told ABC News. "To me, he looks like a juvenile."
The court has ordered ossification and dental tests to be conducted within the next three days. In addition, two witnesses will be interviewed by the court. A ruling will be made by the end of next week.
After weeks of delay, Kasab's trial finally began last week only to be dramatically delayed again when Kasab's court-appointed defense attorney Anjoli Waghmare was dismissed due to "professional misconduct." Waghmare was not only representing a victim in the Mumbai attacks but the same person was also a witness in the case against Kasab.
Kasab is believed to belong to the Pakistan-based terror group Lashkar-e-Taiba.
The trial is delayed until May 2 to give Kazmi, the newest attorney, a chance to review the case. The trial is being conducted with a judge and no jury because of security fears and is expected to last six months.