All eight female members of the royal family, including Princess Aiko, will lose their royal status when they get married. The emperor's daughter, Sayako, formerly Princess Nori, joined the ranks of "commoners" when she married a Tokyo City government employee in 2005.
Oshima said one of the concerns for the future is a lack of members within the Imperial Family. "By the time Prince Hisahito is at an adult age and is expected to tend to official duties, most or possibly all of the female members could be out of the family under the current law," Oshima said.
"It would be a heavy load for Prince Hisahito and for other male members of the family to carry. Of course, you cannot deny the possibility of more male heirs to be born in the near future but someone should take a look at the status quo if we are serious about preserving the ancient monarchy."
"Politicians may say they deeply care about the royal family but no one will dare to touch such a delicate issue," Oshima said.
"I am not saying Japan needs to have a female emperor but it is high time to put our heads together if we are serious about maintaining this system. We should at least look at some options, including allowing female members to keep their status as members of the royal family so that they can all share and continue to fulfill duties."
Crown Prince Naruhito made a controversial statement in 2004 in an attempt to "protect" his wife, just like he pledged when he proposed to her.
"It is true that there were developments that denied Masako's career as a diplomat as well as her personality," he said, adding his wife had "exhausted herself" as she tried to adapt to life inside the royal family.
The statement suggested friction between the couple and the agency. "I think it was cool for the Crown Prince to come out and speak on behalf of his wife," said Tomoki Hayashi, a 23-year-old Tokyo businessman.
"Since the agency has not been able to back her up, the Prince must feel he is the only one who can protect her. The agency should not force things on the family just because it is tradition. Things change over time and they need to be more flexible and adaptive. I am single but I hope I can be a husband just like the crown prince."
The family has continued to surprise the nation in the past few years by making a series of unusually candid comments at news conferences.
At a news conference in 2006, Emperor Akihito said that it was "unfortunate" that he had not had many opportunities to see his third granddaughter, Princess Aiko.
At another news conference a few months later, the crown prince said that he would like to create more opportunities for his daughter Aiko to visit with the emperor and empress.
"If my in-laws say on television that my kids do not visit them as often, I will not quite know how to respond to that," said Rika Kayama, a psychiatrist. "They should feel comfortable talking to each other in private more freely but the series of recent comments suggest a line of communication may not be totally open."
Kayama said the lack of communication also seems to extend outside the palace. "Taking Princess Masako, for example, we really do not quite know how she is doing," Kayama said.
"I am sure she is doing what she can to get better but the public is not well informed about her condition."
The Japanese public has not even heard Princess Masako's voice for several years.