Was it lese majeste or just a good laugh? Scurrilous libel or a witty commentary on a topical issue for Spanish parents?
A court in Spain has convicted Manel Fontdevila, cartoons editor of the popular satirical weekly magazine El Jueves, and cartoonist "Guillermo" of "damaging the prestige of the crown".
El Jueves poked ribald fun at the royal coupleBoth men received a hefty 3,000-euro (£2,100) fine.
Their offence was to have published a cartoon last July making ribald fun of the heir to the Spanish throne, and of the government's scheme to encourage women to have more babies by giving mothers a special payment for each new birth.
It was a caricature of Prince Filipe having sex with his wife, Princess Letizia, and telling her: "Do you realise that if you get pregnant, it will be the closest thing to work I've done in my life?"
The problem, writes William Horsley of the European Union of Journalists, is that such a case is emblematic of eroding media freedom in Europe:
Miklos Haraszti is Europe's chief enforcer of media freedom on the governments and courts of the 56 member states of the OSCE (Organization for Security and Co-operation in Europe).
He says that oppressive laws against the media, intimidation and threats of dismissal, are all being used as weapons to censor the work of journalists in Eastern and Western Europe today.
The latest evidence for that harsh verdict comes from a Survey of Media Freedom in 20 European states presented to the OSCE's Representative for Media Freedom last weekend. The study, entitled Goodbye to Freedom?, was published by the independent Association of European Journalists.
'Unusable' laws
It finds that within the past year alone, journalists in 18 out of 20 European countries - including would-be models of democracy like Germany, the Netherlands and France - have faced criminal prosecution, or been jailed for breaking various laws that impede them from reporting on matters of public interest. (The two exceptions were the Czech Republic and the UK.)
Yet each year dozens of judgements made by the European Court of Human Rights in Strasbourg overturn the convictions of journalists on libel or secrecy charges in national courts.
So is it really time for the media in Europe to say "Goodbye to Freedom"? Miklos Haraszti says simply that European governments must not pass laws, like criminal libel for journalists, which are "unusable".
The prosecution and conviction of the cartoonists who published a funny sketch of a Spanish prince to make their viewers laugh has chipped away a bit more from the fragile pillar of media freedom in Europe.