It is the sort of proposal which would send the Dowager Countess calling for her smelling salts and the Earl of Grantham steeling himself for social change with a stiff upper lip. After centuries of macho oneupmanship, a Conservative backbencher is now suggesting ending the system of primogeniture for good.
The rule of primogeniture, which sees the succession of hereditary peerages pass to a male even if the son is born after a daughter, has long been a headache for dispossessed females. The problems it poses have driven Sunday night entertainment from Pride and Prejudice to Downton Abbey.
Now it's the 21st century and most viewers of these costume dramas will assume this particular headache is a thing of the past. Women have come a long way. Even the monarchy is changing its succession rules, meaning Kate Middleton's first child - regardless of whether it is a boy or a girl - will become the third in line to the throne.
The stakes may not be as high as in the past, for families of daughter-infested peers no longer face destitution as well as displacement by distant second cousins. But the principle is at stake. And in the view of Mary Macleod, the Conservative MP for Brentford and Isleworth, change is long overdue.
"Women are important to society and they should have an equal role in public life in general," she says. "Hereditary rights is one area which hasn't yet changed. The Queen has led the way on this, with the change in the crown succession. Surely if the monarchy can change to regularise the role of women then so can hereditary peerages."
The issue's importance is underlined by the ongoing role, following the failure of Lords reform, of hereditary peers in parliament's upper House. Ninety of the 92 hereditary peers which sit in the Lords are male. With the government pushing hard to get more women into the Cabinet and on company boards, Macleod says "something's got to be wrong" if the same principle isn't being applied here, too.
"It's about modernity," she argues. "Women should have an equal place to men, and therefore that male precedent of primogeniture should be something that we should review, consult on and ideally do away with so we can have equal opportunity for men and women."
Macleod will bring forward a ten-minute rule bill in parliament this afternoon making her case for the reform. It's unlikely to get anywhere. This mode of introducing legislation to parliament gives MPs a decent platform to put their proposals forward, but very rarely results in an actual change to the law.
Still, moves are afoot in the Lords for a private member's bill to get underway. And with the birth of the Duchess of Cambridge's first child expected later this year, its prospects in one day succeeding to the throne regardless of gender will be getting plenty of column inches. "It's a starting point," Macleod says optimistically. That will give the heirs to Britain's peerages with older sisters something to chew on as they read their newspapers over the breakfast table.