Nigeria has the highest rate of identical twins.
China has the lowest rate at only 1 in 300 births being twins.
Polar bears most commonly give birth to twins.
22% of twins are left handed, compared to only 10% of non-twins.
Researchers suspect that 1 in 8 people start life as a twin but because of miscarriages
of one of the fetuses, only 1 in 70 people are actually born twins.
That's all very interesting but...
What Actually Causes Twins?
There are two types of "Multiple Pregnancy", identical and fraternal.
Identical or monozygotic twins occur when one egg is fertilised by one sperm and the
fertilised egg splits into two or more embryos.
Scientists believe identical twins happen purely by chance and there are no contributing
factors, such as age, race or family genes.
One quarter of all twins are "mirror twins", caused by a late split of the fertilised egg.
This is when the twins are direct reflections of each other.
One will always be left handed and the other will always be right handed.
If one has a birthmark on the left side of their face the other will have the same birthmark
on the right side, and so on.
But the reflection is more than skin deep, one of the twins will have their internal
organs on the wrong side of their body, so their heart will beat on the right side.
On the other hand fraternal or dizygotic twins runs in the family.
Fraternal pregnancy happens when two or more eggs are fertilised by different sperm.
Women can inherit a certain gene which causes them to hyper-ovulate, meaning she is more
likely to release multiple eggs during ovulation.
Therefore, increasing the chance of a multiple pregnancy.
So if anyone in your family has twins, or you yourself are a twin, you're much more
likely to have twins yourself.
The Rate of Twins is Increasing Dramatically
The birth rate of twins has increased by 76% since 1980.
In 1980 one in every 53 babies was a twin, however today, one in every 30 babies born
is a twin.
Which, when you think about it, is an awful lot of twins.
But what caused such an upsurge?
One of the biggest factor is that the average age of women having children has risen, and
the older the mother is, the more likely she is to give birth to twins.
Another contributing factor is a rapid increase in the use of fertility treatments that promote
the release of multiple eggs during ovulation.
But enough of that, let's get onto the really bizarre stuff...
There's a "Twin Town"
A small town in Brazil, Cândido Godói is the twin capital of the world.
Amongst the 80 families that live in the town, there are 38 pairs of twins.
Some believe there's something in the water that's causing such such an astronomically
high number of twin births.
But others think there's something much more sinister going on.
Researchers have suggested it may have been caused by a Nazi physician called Josef Mengele,
who had the nickname "Angel of Death".
It has been said that during the 1960s, when the explosion of twins in the town first occurred,
Mengele was performing experiments on the women of the town, involving strange new drugs
and even artificial insemination.
Identical Twins, Aren't Identical
All identical twins have distinguishable qualities from birth.
After all identical twins do have different DNA, their DNA is extremely similar but not
identical.
Identical twins also have completely different sets of fingerprints.
Twins Have Their Own Language
"Idioglossia" is a language shared between twins, that only they understand.
About 40% of twins invent their own language, it sounds complete gibberish to me and you
but it's a close bond shared between the siblings.
This phenomenon can also occur between very close siblings, but more commonly twins.
Their shared language usually disappears by the time they start school.
How Different Can Twins Be?
Very.
Twins can be different genders, but even more astonishing, twins can be different ages.
Recently there was a case where 5 year old Reuben Blake got a brand new twin sister.
Even though they have 5 years between them, they are still, technically twins.
Their mother had difficulty getting pregnant naturally so she turned to In vitro fertilisation
(IVF).
This is when the eggs are fertilised outside of the body then re-implanted into the woman's
uterus.
But Reuben's mother only had two of the embryos from the process implanted into her uterus,
the other three were frozen.
A few years later she had the remaining embryos implanted and 9 months later she gave birth
to Reuben's twin sister.
Believe it or not twins can have different dads and be different races.
It's rare, but about 2% of fraternal twins have different dads.
This happens when a woman releases two eggs during ovulation and then gets impregnated
by two different men at the same time.
Twins Bond in the Belly
We've all witnessed the unbreakable bond that twins often have, but where does it come from?
Twins actually bond physically in the womb.
Researchers at the University of Padova in Italy noticed via 3D ultrasound that at 14
weeks old, fetuses reach out for each other in the womb.
At 18 weeks old they were stroking each other and maintained physical contact 30% of the
time.
Strangely, in these tests the fetuses avoided touching each other's eyes, as if they know
it's a delicate area.
So now you know all about twins, but the story I'm about to share with you will blow your
mind, introducing...
The Twin Jims
The prize for the most incredible twin story has to go to Jim Lewis and Jim Springer.
They were born in 1940 and adopted by separate families in Ohio.
They grew up 45 miles from each other and had no contact for 39 years.
When they were reunited in 1979 they discovered that they were both named James by their adoptive
parents, they both married twice, first to women named Linda and secondly to women named
Betty.
They both had children, Jim Springer had a boy whom he named James Allan and Jim Lewis
named his son James Alan, with one L. They both had dogs named Toy.
They both drank the same beer, smoked the same cigarettes and drove the same model of
car, Chevrolets.
Their medical histories were identical and they shared the same hobbies, including a
woodworking workshop in both their garages.
They both had vacations on the exact same beach in Florida.
Simply incredible.