"You gotta love livin', baby," Frank Sinatra famously observed, "because dyin' is a pain in the ass."

Gingerly, then, to Vanity Fair's forthcoming interview with Mia Farrow and eight of her children, which sounds almost designed to make Woody Allen wonder if death were quite the terrifying pain in the ass the director has always held it to be. I'm afraid that old cliche "uncomfortable reading" wouldn't really appear to cover this one. On the very off-chance that Woody reads it, it may momentarily throw dying into hugely sympathetic relief.

The interview-cum-profile appears in the November issue of the magazine, and runs the gamut from the merely grotesque – the pair's daughter wonders how Woody has the gall to tell her that his daughters with stepdaughter-turned-wife Soon-Yi think of her as their sister – to hitherto unspeakable horrors. "What happened in the attic I remember," avers Farrow's daughter Dylan, whose sexual abuse Allen denies.

As for Ronan, always described as Woody and Mia's "biological son", in that casually horrible way people have of differentiating between adopted and "proper" children – well, it turns out he might be the non-biological version. Asked outright by Vanity Fair if Ronan is Sinatra's son, Farrow replies: "Possibly." On front pages around the world, pictures of the blond, blue-eyed boy have duly appeared next to ones of Sinatra and Allen, and though the Daily Mail has ducked out of war on another front by opting against the headline: "Does he look like a Konigsberg to you?", the DNA test of public opinion has already spoken.

So too has Young Blue Eyes, the prodigiously talented 25-year-old Ronan Farrow, who got into Yale law school at 15, has already been tipped as a future president, and this week cemented his reputation for sardonic reflections on his background with a tweeted: "Listen, we're all *possibly* Frank Sinatra's son." Think of it as taking that famous Dean Martin quote – "It's Frank's world: we just live in it" – and grafting it to The Jerry Springer Show. Last year, Ronan chose Twitter to unleash the zinger: "Happy father's day – or as they call it in my family, happy brother-in-law's day." So openly repulsed has he been by Allen that you get the feeling that he is the one guy who watches Rosemary's Baby and envies the nipper its paternity.

That movie, you may recall, was the one Farrow declined to abandon at the request of her then husband, Sinatra, and on the set of which he served her with divorce papers – although, as she now tells Vanity Fair: "We never really split up." Nancy Sinatra emails the mag to declare of Ronan: "He is a big part of us, and we are blessed to have him in our lives."

But if that detail can be enjoyed as a showbusiness curiosity – and a hell of a backstory for one of America's myriad presidents-in-waiting – the rest of the exercise must be to fewer people's tastes. From the exhumation of legal and medical argument about Dylan's sex abuse accusations, including anonymous state investigators speaking with troublingly unprofessional candour about the nitty gritty of what the then seven-year-old child told them, to a sordid rehash of that frenzied court battle 20 years ago – quite why Farrow decided to have the whole thing dredged up again via the magazine is unclear.

It is hardly the sort of thing she would have made her peace with, of course, but re-exposing to the glare of publicity a family whose fragilities and special needs she is keen to foreground seems a high price to pay for reminding the world of the story. If, indeed, that was what she is seeking to do.

For all Vanity Fair's dubiously self-regarding patina of class – it lets Mia bang on a bit about Darfur considering she's given it the motherlode on the domestic horrors – it's just Jeremy Kyle for the liberati.

And this, perhaps, is the most radioactively ironic aspect of Allen's fate: he may be a gossamer-touched director, able to elicit extraordinary meaning and humour from the most slight of vignettes. But the past two decades of his life is widely read as a series of plotlines so scandalously downmarket, so gothic in their grotesquery that even reality TV scriptwriters would disdain them. Perhaps only the Sinatra revelation feels as if it could have a place in Woody Allen's artistic canon – featuring as it does the little guy who marries the ex of this great star, only for it to become obvious that they aren't exes at all, and that he's being cuckolded by the guy who sings New York, New York. That, we can maybe picture him discussing in a comic scene with Alan Alda somewhere.

But the rest – tabloid court frenzies, suggestions of non-biological incest, horrors in the attic – really does belong in some trash-soap netherworld, and there isn't enough blue jasmine in the world to mask the whiff.