The thing is that with the current vogue for double-barrelling on marriage, you then create a problem for the next generation. If two of them have kids, do they have to quadruple-barrel them?

The Spanish system is, in my opinion, exemplary. Everyone has two surnames, one from each parent (rules have now changed on this, allowing the order to be switched and for children to adopt just one parent's names, for cases of messy divorces or abuse).

No one changes their surnames on marriage, but if they have kids, they will get mum's first and dad's first surname, and so on.

In truth the system is perpetuating the name of the maternal and paternal grandfathers - it isn't quite the panacea of sexual equality it seems, though as I say, one can rejig the layout to accommodate personal circumstances.