TOKYO  –  The Japanese parliament has approved a bill to relax imperial succession rules, amid concerns over the dwindling size of the imperial family. The bill, passed by the upper house on Friday, allows the imperial family to adopt distant male relatives over the age of 15 and lets women keep their royal status after marrying outside the family. But it does not change the law barring women from ascending the throne despite wide public support for a female emperor, meaning Princess Aiko, the only child of the current emperor, is still not eligible to succeed the throne.

The bill cleared the lower house last week, and will move through the final legal procedures before the changes take effect.  Japan has the world’s oldest continuous hereditary monarchy, with a lineage that’s believed to span more than 2,600 years. Currently first in line to the throne is 60-year-old Fumihito, the emperor’s younger brother. Fumihito’s son, 19-year-old Prince Hisahito, is second in line. Third-in-line, and the last eligible candidate for the throne, is the emperor’s 90-year-old uncle. Without any amendments to the law, the line of succession will end if Prince Hisahito does not have a male child. However, with the new bill, male descendants of 11 former imperial branches could be adopted back into the family. These family branches had been removed following the Second World War.

There has long been public concern over the lack of male heirs in the imperial family – along with debate over whether women should be allowed to take the throne. Prime Minister Sanae Takaichi and other conservative political leaders have voiced support for male-only succession rules, arguing its importance to imperial legitimacy. However, opinion polls show high public support for a female monarch. In a June survey conducted by newspaper Mainichi Shimbun, involving more than 2,000 participants, more than 70% of respondents said they supported having a female emperor.  Another poll, conducted by Kyodo News, found that 83% of respondents were in favour of allowing a woman to take the throne.