We’ve pondered the question separately — Barbara in her research as a psychologist, Amanda in her writing — and discussed it together, and over time, we’ve landed on a working theory: Twins indulge the fantasy that it’s truly possible to have another half. As psychotherapist Vivienne Lewin, author of , “the idealization of the twin relationship is based on essential internal loneliness.” We all want to find someone who understands us intimately, and who better than someone you’ve known since before you were born?“The myth of twinship,” Lewin argued, “is one of perfect companionship and understanding.” a myth.As Amal and Beyoncè welcome their twins into the world I imagine they're pondering this exact debacle...

'We've essentially never fancied the same guy, our significant others are significantly different to each other and to that classic age old question of, 'Have you ever thought of swapping? Because we're not cave men and it would be f*****g weird.' I couldn't have said it better myself.

When you’re a twin, it’s hard not to notice how fascinated the rest of the world is by your sibling relationship.

Especially in childhood, maintaining closeness and harmony between twins can be hard work.

Beyond the usual rivalry and spats between brothers and sisters, there’s the additional pressure and frustration that comes with always being lumped in with, and compared to, another person.

The two of us can speak from direct experience: Barbara has an identical twin sister and Amanda has a fraternal twin brother, and we’ve both spent much of our lives fielding questions about what it’s like to share a life with someone you once shared a womb with.

We’ve also spent plenty of time thinking about the source of all this intrigue: What is it, exactly, that people find so fascinating about twins?In my grown up brain, I decided "So my friend wants to get with my girlfriend's identical twin, which sort of means they want to get with my girlfriend? 'We're at a themed party but because we're idiots we've both come as the same character.In short, there's ginger wigs left, right and centre and if you look closely there's two boozy copper tops running around with the same face.'Out of the corner of my eye I keep noticing the wavering arm of George's boyfriend Tom almost going around my waist, but stopping just short, knowing something is a little off.They've been together for over 8 years but a heady combination of Jack Daniels, musical medleys and matching wigs has caused havoc.'But it's Frank's utterly unique personality, outlook and her distinct way with words that properly attracts me to her (not to mention our mutual love of watching copious amounts of Food Network whilst smashing a Dominos Two for Tuesday).