You know that moment when you meet your partner’s sibling for the first time and they look so identical that during a family dinner at Gran’s place, you accidentally go to put your arm around your significant other, only to realise that he’s still in the lounge room and you’ve been flirtatiously lingering by his brother’s side for the last three minutes?
It’s the dilemma of dating an identical twin.
When I first met Rowan, Stuart’s double, I was pretty overwhelmed by their similarities. They shared the same mannerisms, they both (irritatingly) pronounced it ‘ezzactly’, and of course, their general appearance was hugely alike (I like to think of it as 'a face so good, reproduction had to make two'). But these matches only aligned to a degree. Although I’d be more than happy to indulge my fantasies of clones and doppelgängers walking among us, the reality is that twins are two different people. Even though Rowan and Stuart look the same, they are a prime example that identical twins aren’t always exactly identical. After 30-odd years of living, Rowan and Stuart have lived different lives. They are subject to different stresses, have consumed different foods, lived in different climates and broken different bones. These effects which alter a person’s appearance, counter the common misconception that identical twins are forever as doubled as B1 & B2.
But who doesn’t have fun with a pair of twins, right? Recently, a trip to the mall was a hilarious excursion, where I stood and watched identical twins buy identical shoes. I’m not sure seeing double was as entertaining as the sales assistant’s expression, trying to keep a straight face. We didn’t spend long, we didn’t require two different sizes, but it was here that I noticed Rowan taking his shoe with his right-hand and trying it on his right-foot and Stuart doing the opposite with a left-handed, hand-foot-combo. They were reflecting each other, like a mirror image.
Mirror twins are identical twins whose fertilised egg split later in the zygotic stage – between 9-12 weeks, which is just shy of the formation of conjoined twins. Dr Stephen Robson, an experienced obstetrician and gynecologist says, that aside from their asymmetrical characteristics, mirror twins are significant because of the insight they give into how embryos form and consequently, how many the characteristics (like whether a twin is left or right-handed) are evidently mapped out by our DNA.
“You can also look at mirror twins as a near miss of being a conjoined set of twins and maybe mirror twins should consider themselves as really lucky that they didn’t end up being in that situation,” he says.
Interestingly, there is no DNA testing which can distinguish mirror twins and instead, their features and characteristics have to be observed. These mirror asymmetries includes, dominant-handedness, dental patterns, birth marks, hair whorls and body abnormalities like, in Rowan and Stuart’s case, a slight twist in one earlobe. So, even though there’s no official mirror twin stamp of certification, if you’re an identical set of twins and share asymmetric characteristics, it’s highly likely that your zygot split in the later stage. In some extreme cases, mirror twins can even have asymmetrical organs or reversed skeletal features, but of course, they’re not allowed out of the lab.
Just kidding! However, twin studies are a vital contribution to scientific research. Throughout history, psychologists, scientists, sociologists and the general public have debated the nature vs. nuture precedence and wondered what of our human make-up is inherent and what is learned behavior. Associate Professor of Paediatrics at the University of Melbourne, team leader in Environmental and Genetic Epidemiology Research at the Murdoch Children’s Research Institute and the Dept Director of the Australian Twin Registry, Prof Jeff Craig says that, over the last 20 years twin research has overturned certain assumptions about nature vs. nurture or as he puts it, “nature via nurture – you always have both.”
“It was thought that epilepsy and schizophrenia were environmental, and it was something that the mother or the obstetrician was responsible for,” he says. “But now we know that there is a large genetic component, as we found identical twins discordant this particular disorder."
Feeling inspired by Prof. Jeff Craig’s work, I decided to conduct a twin study of my own. In the most bizarre way to get acquainted with my boyfriend’s brother, I interviewed Rowan and Stuart, one at a time with the same questions on their thoughts, opinions, likes and dislikes. Neither twin knew any questionnaire before undergoing my ‘experiment’ and importantly, neither knew the other’s answers. Any similarities would be down to the amazing, fantastic, spooky miracle of genetics ... or possibly, just a coincidence.
I wanted to see if these mirror twins' answers reflected one another’s in a way that would satisfy my giddiness when I see a double-pram, why Rugrats' Phil & Lil were my cartoon characters and the reason I’m always that annoying guest at dinner parties who asks, “can you feel each other’s pain?”.
To find out more about twins watch Insight: Twins, Part 1 | Tuesday 15 March, 8:30pm, SBS