Steve Sailer links to this fantastic New Yorker comic:
Ouch! Please report to the burn unit of the hopsital!
This hits so many outrageous buttons at once: 'incisively observing an unusual but true correlation', 'needless withering putdown of other people's dubious choices' and 'old school snobbishness' all in one.
I went through the list of people I knew with tattoos for P(Divorce|Tattoo), and it went 'Yep...Yep... Nope...Yep...'. Okay, what about the other direction, of the non-tattoo folks for P(Divorce | No Tattoo)? 'Nope... Nope... Nope... Yep...Nope... Nope.. .'
If you, like me, are not particularly enamored of the spreading of this social trend, there are far more eloquently reasoned and interesting critiques of tattooing (for instance, this great Theodore Dalrymple essay), but as Mr Mencken put it, one good horse laugh is worth ten thousand syllogisms
As to why the underlying correlation exists, I think it works on two levels.
One is the treatment effect of traumatic parental events in a child's upbringing. Part of the appeal of tattoos (as far as I can tell) is the notion of their permanence - being able to inscribe something on yourself that will stay fixed, committing an idea or picture to permanent association with yourself. I can imagine that this desire is subconsciously more sought out by people for whom a significant event in their childhood was the disruption and dissolution of the home life they'd thought of as permanent.
The other is the likely heritability of time preference, and compulsive decision-making more generally. I can imagine that the kind of parent who enters into a rash marriage, or decides to have an affair with the secretary or mailman, will (through probably both genes and culture) result in a child who will think less about how the tattoo is going to look when they're 50 with wrinkled skin, or 26 and applying to the law firm.
Still, whatever the reason, I'm mentally filing this one away in the list of life's correlations to bear in mind when one needs to get all Last Psychiatrist in one's analysis of a person.