Twins: Is life as a twin double trouble or just twice as nice?
As the world welcomes a new set of royal twins in Monaco, Kerry McKittrick meets some of Northern Ireland's identical siblings
At just under a month old, Jacques Honore Rainier and Gabriella Therese Marie have just made their debut public appearance.
The fraternal twins are the first children born to the Crown Prince of Monaco Albert and his wife Princess Charlene. As such, Jacques will one day inherit the throne of the principality of Monaco, and currently holds the title of Marquis of Baux.
The twins, who also have a half-brother and half-sister from their father's previous relationships, are destined for a life of luxury and there'll be no shortage of help and support when it comes to bringing up the royal babies. Fraternal (non-identical) twins such as little Jacques and Gabriella occur around once in every 60 births, with identical twins occurring around one in every 250 births.
Fraternal twins - essentially two ordinary siblings who happen to be born at the same time - also tend to run in families. Identical twins are less common and while it was originally thought there was no hereditary link, recent research has suggested that a genetic predisposition may exist.
We talk to two sets of twins about their special bond and what life is like with an identical sibling.
'We get the odd stare when we're on the street'
Jennifer McKenna (29) is a beauty therapist and part-owner with her twin sister Angeline of Perfection hair and beauty in Dungannon where she lives. She is engaged to Ryan Quinn. She says:
I'm older than my twin Angeline by 11 minutes and we are identical. I don't know what it's like to not be a twin. We're equals in everything so I'm no more protective of her than she is of me.
Because we look alike, we do get stares and double-takes in the street and that can get to the point where it's annoying. We don't get comments, although when we go out for a night you get the odd sleazy man saying something.
Angeline and I are very close, we share the same friends. We both live at home still and won't be moving out until we get married. It will be a little strange then. Angeline has her wedding booked for 2016 and I only got engaged on New Year's Eve.
The family have always called us 'Twin', both seperately and jointly. I find it a bit rude as they could call me by my name. We're the youngest of eight, though, so we don't have much say. We now have twin nieces too but they get called Twinnies so we don't get mixed up. There are quite a few sets of twins in the family.
We played a few pranks at school and would often go to each other's English classes, but no one ever noticed.
Angeline used to have a part-time job at the weekend. She took a few weekends off and one weekend she wanted to go away with her boyfriend but couldn't get the time off work. She sent me in with a very close friend who worked there to cover for the day. The friend showed me what to do and I was quite happy to get a few pounds. No one ever knew, even though I did it for a few weekends.
We've only felt each other's pain once. I split my head open when I was about four or five and mum had to rush me to hospital. I didn't feel a thing as I was probably in shock but Angeline was running around home with our dad holding her head and saying that it hurt. It's the only time that's happened."
'We sometimes finish each other's sentences or say the same things'
Angeline McKenna (29) owns Perfection Hair and Beauty Salon with her sister. She is engaged to Conor Lynch. She says:
When I get married it will be strange because I'll be moving up to Dungiven and Jennifer and I have never lived apart. We'll still be working together, though, so it's not like I'll never see her.
Jennifer and I are what's called mirror-image twins. If we sit opposite each other at a table eating, one of us will hold her knife and fork in the wrong hands to mirror the other. Even the partings in our hair are on opposite sides so when we stand facing each other we look the same.
It's totally unconscious and it's a phenomenon that some twins have. We don't have lots of those kinds of things, though, just those wee quirks. Some mirror image twins evens have their organs on opposite sides.
We often speak at the same time, finish each other's sentences or use the same phrases, but I think that's just because we're with each other all the time and any other pair of close sisters would be the same.
We are also very in tune at work because we've been a team for so long - she knows exactly how long it takes me to do one treatment, and vice versa.
There are plenty of twins in the family so I think there's a chance Jennifer or I will also have twins.
Our mum is a twin and our sister has had twins. We also have twin cousins and second cousins."
'Playing against him can be strange'
Aaron Burns (22) plays football for Linfield. He lives in Banbridge. He says:
I'm the older twin by seven minutes and we're identical twins although we've become a little different as we got older. It's actually triplets that run in our family rather than twins but one died in the womb and didn't make it. We also have three half brothers and three half sisters.
Mum used to dress us in the same outfits until we were about 11, when we put our foot down and told her to stop.
People do struggle to tell us apart. Mum is the only one who can do so but dad just guesses and hopes for the best.
We didn't actually play many pranks in school - we were in the same class the whole way through so would couldn't swap places in each other's lessons. And when it comes to education, we have stayed together - now we both go to the University of Ulster, Jordanstown.
Playing football against each other can be a little strange. We know each other's style so well it can be difficult to play a game of football together. We always played football together since starting at school. People talk about twins being able to feel each other's pain but it's only happened to us once.
When we were about 10 I had a hernia operation on my groin and Andrew started complaining of pain when I was having the procedure.
We are very close. We still live together at home and last year we started a football coaching business. We don't mind working together at all.
Like most people, we disagree sometimes, but we don't actually fight.
We just leave each other alone for a while and then come back to the problem later.
We don't finish each other's sentences and to be honest if I started speaking for Andrew I don't think he would be too happy. I do tend to be the more outgoing one, though.
I think it's hard enough to have twins - you need to have two of everything."
'People do mix us up, but not on the football pitch'
Andrew Burns (22) plays football for the Dungannon Swifts. He says:
Everyone treats us the same and we treat each other the same. I don't feel like the younger twin or that Aaron is my big brother.
My girlfriend can tell us apart, but I don't know how. People mix us up on a daily basis but not on the football field. We've thought about going to each other's football practice but Aaron kicks with his left foot and I kick with my right so if I got put on the left hand side of the pitch for Linfield I would probably end up falling over. We're both left-handed, though.
We would have kept a few people going when we were younger but we didn't go in for pranks much. We were in the same classes all the way to late secondary school, then we did different A-levels and we're doing different subjects at university. Aaron does sports and I do business management. The idea is that we combine the two in our coaching business.
We started playing football at around age seven for Banbridge Town Juniors. We always enjoyed it and it was always something we wanted to do. I think it was mum and dad's worry that one of us would be signed up to a football club and go off and leave the other behind but when we were 16 we both signed to Leicester City.
We struggled a bit so we came home and both signed for Linfield, then I went off to Portadown and then Dungannon. It was strange to play for a team without my brother at the time but you just have to get on with things and get used to it.
Being a twin was always good for me and Aaron growing up. If you started something new or went to a new school then you always had someone there with you. Mum and dad have never worried about either of us being lonely. We live and work together and go out at the weekend together."
Famous faces who share that special bond ...
- Ashton Kutcher, Gisele Bundchen, Scarlett Johansson, Alanis Morissette and Kiefer Sutherland are all fraternal twins, which occurs when two separate eggs are fertilised by two separate sperm. Fraternal twins can be the same or different sexes with the same or different blood types. Identical twins occur when a single egg fertilised by a single sperm splits in two. Identical twins are always the same sex and always the same blood type.
- Identical twins James and Oliver Phelps are best know for their roles as the Weasley twins in the Harry Potter films. They have also appeared in the TV series Kingdom.
- Mary-Kate and Ashley Olsen are fraternal twins and made their acting debuts as infants on the TV show Full House. They went on to other roles before starring in their own show, The Adventures Of Mary-Kate and Ashley.
- Identical twins Matt and Luke Gloss rose to fame in the 1980s as the boy band Bros. Luke has gone on to have a successful film career including a role in Hellboy II. Matt still works as a singer and songwriter, with live shows in Las Vegas and London.