One of the great advantages of the family history boom is that most of us have been obliged to give up what Freud called the “family romance” — the belief that we are related, a couple of generations back, to people richer, grander or cleverer than boring old us.

Finally letting go of the fantasy that Cleopatra was our eight-times-great granny or that we are the spit of the Duke of Wellington, the way is open for a set of less elevated, though actually more revealing, ways of understanding both the personal and public past.

According to a poll from Ancestry, an amateur genealogy website, you are far more likely to discover that your grandparents weren’t married or your great uncle was married twice — but at the same time — than you are to learn that Prince William is your third cousin. Dig below the topsoil of your current existence and chances are you will uncover a family tree that, far from being a sturdy oak, is actually an elm, riddled with illegitimacy, informal adoptions, changed names and convictions.

At first glance this might prove disappointing. Not so much that there isn’t a duke tucked away somewhere as that the scandals are so damn ordinary. Learning that most of your ancestors turned crispy in the Great Fire of London would at least give you the sense of being tied into the grand narrative of history.

But discovering that they spent most of their time clinging to the perch of respectability, and sometimes falling off, is hardly the stuff dinner party anecdotes are made of.

It is, though, a great way of cutting through all the flabby rhetoric about “how things were” 50 or 100 years ago.

To listen to some people, you would be forgiven for thinking that not all that long ago people left their doors unlocked, young couples couldn’t wait to walk up the aisle and men felt honour-bound to stand by girls they had got pregnant.

Now we are catching up with our recent ancestors, thanks to all the documentation (civil registers, the census) online. And what those family members are telling us, crucially, is that their lives were really no different from ours — and that, by extension, we have nothing much to be ashamed of.