Do people get their politics from their parents?
Labour Party leader Ed Miliband is locked in a row with the Daily Mail over his father's views. But to what extent do our mothers and fathers shape our political opinions?
Many people's first exposure to political debate wasn't watching Question Time or reading newspaper reports about the House of Commons or the US Congress.
It was at the dinner table or in the family front room, with a parent cursing conservatives or muttering darkly about socialists.
Labour leader Ed Miliband's upbringing fitted this pattern better than most. His father Ralph was a left-wing academic, his mother Marion a campaigner for progressive causes.
Now this family history has become the focus of a bitter media spat. On Saturday, the Daily Mail ran a profile of Ralph Miliband under the headline: "The man who hated Britain". After offering his son the right of reply, the paper repeated the original article and ran a leader describing the deceased lecturer's legacy as "evil".
For its part, the paper justified the attack by arguing that Ralph Miliband's political views had been passed down the generations.
"We do not maintain, like the jealous God of Deuteronomy, that the iniquity of the fathers should be visited on the sons," its leader says. "But when a son with prime ministerial ambitions swallows his father's teachings, as the younger Miliband appears to have done, the case is different."
The Labour leader has reacted furiously.
He insisted his politics were markedly different from those of his Marxist father: "I have pursued a different path and I have a different vision." He also said he was "appalled" by the Mail's "character assassination" of a man who had served in the Royal Navy during World War II after escaping Nazi persecution.
The dispute raises the question of the extent to which people's politics are shaped by the influence of their families.
Many of those who have backed Miliband in the row have followed the Mail's logic by pointing out that the first Viscount Rothermere, great-grandfather of its present owner, met Hitler and wrote an article titled Hurrah For The Blackshirts in 1934 which praised Oswald Mosley's fascists.
There are plenty of political dynasties, even in countries that have long shaken off the shackles of aristocracy - the Bush family, for instance, who have accounted for two of the last four US presidents, or the Gandhis in India.
In the UK, the Cecil family have been involved in Conservative parliamentary politics for more than two centuries, while four generations of Benns have sat for Labour or the Liberals in the House of Commons.
But there is no shortage of examples of politicians who have rejected the views of their forefathers.
Famously, the father of former Conservative cabinet minister Michael Portillo was a left-wing Spanish Republican who escaped his homeland during the civil war. Labour Prime Ministers Clement Attlee and Tony Blair both grew up in Tory households (Attlee's grandson, Earl Attlee, now takes the Conservative whip in the House of Lords).
If nothing else, the process of youthful rebellion requires adopting contrary views - teenagers in the Tory shires long having irritated their mums and dads by joining the Socialist Workers Party or announcing their sympathy for the anarchist cause.
It's a process the comedian Alexei Sayle understands well. He grew up in a Communist Party household in Liverpool where the only way to appear more radical than his parents was to declare himself a Maoist.
Over time, however, Sayle, while retaining left-wing principles, lost his illusions about the brutality of the regimes his family supported. As a result, he feels ambivalent about the environment in which he acquired his values and moral code.
"My parents had a genuine hatred of injustice - they were really decent people. On the other hand, that wish for a better world led them to turn a blind eye to the two greatest mass murderers of the 20th Century, namely Stalin and Mao," he says.
"But I'll always value the fact that they taught me to look sceptically at the news, to question society and people's motives."
It's not just among the left that parents can be crucial in shaping opinions. Margaret Thatcher often spoke of the formative influence of her father, a grocer and Methodist lay preacher, who instilled her faith in the virtues of hard work and thrift.
Of course, plenty of children of politicians and the politically engaged grow up to have no interest whatsoever in parties and ideologies.
Others say they became active despite, not because, of their parents' interests.
Rachel Johnson belongs to one of the most notable political families in the UK - her father Stanley was a Conservative MEP while her brothers Boris and Jo serve as Mayor of London and head of the Number 10 Policy Unit respectively.
But she insists that politics was rarely discussed while she grew up, not least because her parents' affiliations were split - her mother Charlotte was a Labour voter.
"We didn't have a politicised household," Johnson, herself a Conservative party member until recently, says. "The only thing I remember was canvassing for my father for the European Parliament. But we did that not because he was a Tory but because he was my father."
Arguably the political success of the Miliband family is proof that politics aren't simply handed down from father to son.
It's difficult to reconcile the Marxist dialectics of Ralph with the views of his Blairite son David, who served as foreign secretary from 2007 to 2010 and was defeated by his brother for Labour's leadership.
Though Ed has often spoken warmly of "the values I grew up with", he rose to the top of the party in defiance of his father's long-standing belief that Labour could never achieve socialist transformation.
Unite general secretary Len McCluskey once joked that Ralph Miliband "spent his life trying to convince our movement that there was no possibility of a parliamentary road to socialism, while his sons have been loyally putting theory into practice, and proving Ralph right".
Still, when children depart from their parents' political paths delicate situations can arise.
In 1994, Sir Nicholas Scott, the Conservative disability minister, left office after coming under severe criticism after the government scuppered a bill that would have banned discrimination against disabled people.
One of his sternest critics was his daughter Victoria, a Labour party member who at the time worked for a disability pressure group. Memorably, on one occasion she took to the Today programme to sternly criticise him.
Now Victoria says the affair did create tensions, even in a family where she had been encouraged to think independently (Sir Nicholas later told interviewers he was proud she had stood up for herself).
"My dad loved arguments and had a good sense of humour - he'd rather I was left-wing and had different political opinions than that I was totally uninterested," she says.
"But we weren't prepared for the emotional and personal fallout, which was quite phenomenal. People in my family really felt I had betrayed my father, even if he didn't feel that himself."
Her experience may be far from uncommon, according to Elias Dinas, lecturer in politics at the University of Nottingham, who has researched the impact of parental influence on opinion-forming.
"There's a volume of literature that says the more politicised your parents are, the more likely you are to become a politically engaged adult - but you're also more likely to abandon your parents' views," he adds.
If true, this implies the best way to pass on your political opinions to your offspring is to keep quiet about them. In the Miliband household, this evidently wasn't an option.