Semen really brings out the best in journalism, doesn't it?

Media hysteria surrounded the trial of Wayne O'Donoghue, tried for the murder of Robert Holohan.

Meejit is no meeja snob. As well as being tragically sad, the O'Donoghue-Holohan case is a good story, with elements of mystery and empathy to go with the tragedy. Nonetheless, the litany of lowly media sins in the case, the first of which were well documented in last week's Village, lengthened and worsened as time went on.

Majella Holohan, for example, found her every brief driveway chat billed as an "exclusive interview". And in the case of the Evening Herald, what appeared to be her actual words to reporters were insufficient for the headline-writers. "'He groomed my Rob'," the paper's front screamed; it re-used that disgusting piece of alleged paedophile lingo, again in inverted commas, in the page-4 headline, "'Wayne groomed my little Robert'."

But nowhere in the report is she quoted using "groomed"; she says Wayne bought gifts for Rob. As for the Herald's other page-1 quote, "Wayne O'Donoghue is like Ian Huntley in Soham", a turn of the page reveals her saying nothing of the sort: she compares the jail sentences, not the men.

Newspapers happily played the "Poor Photogenic Wayne" card during his trial, despite the widespread rumours (Meejit heard them coming from the highest level of the Garda in Dublin). They even more happily turned him into a stereotypical monster given the opening. The tabloids probably would have done so anyway, without Majella's help: they decided long before Wayne that a criminal conviction usually makes defamation a purely academic question.

More respectable media tended to tsk-tsk haughtily about Majella Holohan's intervention, but mostly failed to ask more fundamental questions about the events and interests that brought the case to this strange and unresolved pass.

To Meejit's knowledge, only the Sunday Tribune began to probe deeper at the key role of "expertise" in criminal investigations. A good defence lawyer in the O'Donoghue case put on the pressure and turned a "definitive" ID of a trace of semen into one that was so questionable it daren't be presented in court. Undoubtedly the forensics lab in this case behaved honestly, but it raises profound questions about the confident use of "science" in such investigations, and the media's incurious belief in it.

It's not as though we haven't been given some red flags on these matters. Recently we've seen the dreadful but little-discussed case of the American lawyer, a convert to Islam, who was picked up as a suspect in the Madrid bombing because of an alleged fingerprint match – and freed only when the Spanish police got their man. It is certainly plausible that in some cases the "experts" know what police are looking for and give it to them without publicly acknowledging their potential scientific doubts.

In the O'Donoghue trial there were small but significant differences in interpretation of Robert Holohan's injuries between a pathologist from Northern Ireland and one from this State. This suggests a margin of error in such interpretation that is rarely recognised.

In place of such relevant questions, tabloid papers were content to partake of more paedophilia hysteria, straight out of the British journalistic culture that has recently enjoyed one of its periodic paroxysms.

It's worse than ironic that these same papers happily embrace the freewheeling sexualisation of all aspects of popular culture, including the marketing of sexually driven TV shows like Big Brother and Friends as fun for all the family.

This column pleads not-guilty to prudery as well as snobbery. But it's a bit rich to soak society in sex (already a pretty damn powerful impulse) and then pretend you can draw a solid and unbendable line between the predatory monsters and the rest of us. Abuse of children is, of course, a horrible crime. But how many people, after all, have had youthful experiences – "coming of age" rites, "sexual initiations", famed in song and story – that would never withstand the scrutiny of today's sex police?