If the child does turn out to be a girl, she is destined to ascend the throne as queen one day.

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But the drafters of the first Imperial House Law decided not to allow women to ascend the throne in order to preserve the single line that, according to legend, is descended from the sun goddess, Amaterasu Omikami.

CNN: IN HER OWN RIGHT

Scotland's First Minister Alex Salmond also welcomed the lifting of the ban but said it was "deeply disappointing" that Roman Catholics were still unable to ascend to the throne.

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For a secretary of state to ascend to the throne of St Peter is rare: the only example since 1667 was Pius XII, in 1939.

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