A government panel discussing ways to ensure a stable imperial succession unanimously approved on Monday a draft report outlining two proposals.
The two options — allowing female members who marry commoners to retain their imperial status, and male heirs from former branches to be adopted into the imperial family by revising the 1947 Imperial House Law — seek to address the dwindling number of eligible heirs.
Under current rules, female members have to leave the family upon marrying a commoner.
But the panel is expected to postpone its conclusion regarding specific measures on succession, such as whether women or matrilineal imperial members will be eligible to ascend the throne, which were not included in the draft outline.
The law limits heirs to a male who has an emperor on his father's side.
Currently, there are three heirs in line to succeed 61-year-old Emperor Naruhito — his brother Crown Prince Akishino, 56, his nephew Prince Hisahito, 15, who is the crown prince's son, and the emperor's uncle Prince Hitachi, 86.
Former Keio University President Atsushi Seike, who chairs the advisory panel, told reporters following the meeting he intends to submit a finalized report to the government at a meeting to be held within the month.