On a long drive home last night, I was annoyed to find the airwaves filled with the not very interesting news that a baby had been born in London - three or four hundred are born there every day, but this one gets particular hereditary privileges which I suppose make it worth a few seconds of one's attention.
So I turned the radio off, and wondered - I like to exercise my critical faculties - what the news was lying about. The suspicious part was the claim that the sex of the baby had been a surprise to its parents. That could be true, but it doesn't follow that no one knew. Ultrasound scans will certainly have been performed as part of the mother's care, and the ultrasonographer will certainly have observed the fetus's genitals.
The sex was of unusual importance (that is, fractionally more than none) in that the Succession to the Crown Act 2013 makes "succession to the Crown not depend on gender". So, had the baby been a girl, it would have been likely eventually to become queen, and, contrary to long-standing practice, that would remain the case if brothers were later to be born. Which would make the ratification of the Perth Agreement a matter of some urgency, at least in the minds of courtiers who care about such things. It follows that they would have strained to discover from the ultrasonographer the sex of the fetus, and, had it been female, to publicize the fact so as to concentrate the minds of the other Commonwealth Realms. Whereas had it been male, as it was, there would have been no hurry.
It could therefore be deduced from the secrecy about the child's sex that it was male. I recognize that this analysis would be more impressive if I'd written it without knowing the result.