30 fascinating facts about twins - Giving birth to twins is more common than it was 30 years ago. One of the reasons is that women are choosing to have children later in life, which according to research increases the chance of a double pregnancy. The twins' world is complex and sometimes misunderstood, and one full of unanswered questions. But there'll be no need for double takes after browsing this gallery of facts surrounding the lives of twins.

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Biological parents may be different - The chances of it occurring are a million to one, but twins born to different biological parents can happen. In 2009 a case in North American recorded that a one Mia Washington had two eggs fertilized by two different partners during the same month. Nine months later she gave birth to twins.

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Can twins fool dogs? - Identical twins can fool even their parents, but do they fool dogs? A survey conducted using old German shepherd dogs demonstrated that canines can indeed tell twins apart by identifying each of their unique odors.

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The same difference - At just four weeks of age, a pair of twins both named Jim were separated, with each being adopted into different families. When they met years later, Jim Lewis and Jim Springer discovered that they both had a dog named Toy, drove the same make of car, drank identical beers and smoked the same brand of cigarettes.

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Moms of twins live longer - According to a study by The Royal Society, mothers of twins live longer because they are already leading more active and healthier lifestyles. Researchers believe this is one if the reasons twins are born in the first place as healthy mums tend to pass on twice as many genes in the first place.

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Tall moms - Additionally, taller women are more likely to bear twins. A survey conducted by the Long Island Jewish Medical Center found that taller women produce more IGF, a protein that increases a woman's chances of becoming pregnant with twins.

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Dairy products - Eating a lot of dairy produce can up the chances of giving birth to twins, according to a report published in the Journal of Reproductive Medicine. The study pointed out that women who habitually consumed foods high in dairy content were five times more likely to give birth to twins.

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Getting along in the womb - The close bond twins share with each other begins in the womb. The University of Padua, in Italy, discovered that at 14 weeks of gestation, twins in the womb could be observed approaching each other; four weeks later, physical contact had been achieved.

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Early interaction - In addition to communicating with each other from a very early age, identical twins are also very sensitive to the other's feelings.

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Reflexes - About 25% of identical twins face each other while developing in the womb, with surprising results. Mirrored reflexes can cause one to become left-handed while the other is born right-handed, for example. Birthmarks on limbs can also end up being copied in this manner.

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Conjoined twins - In rare cases, conjoined twins, so-called Siamese twins, hear each other's thoughts and see through each other's eyes . This extraordinary phenomenon occurs if the thalamus, the part of the brain that sends physical sensations and motor functions to the cerebral cortex, is conjoined.

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Breastfeeding your twins - When breastfeeding. a mother of twins is able to adapt her body according to the needs of each offspring. Each breast appears to respond to the thermal needs of the infant, reaching different temperatures accordingly!

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Birthrates of twins in Africa - In central Africa, 28 out of every 1,000 pregnancies results in the birth of twins.

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Birthrates of twins in Europe and South America - Europe and Latin America have the lowest rates of twin pregnancies (8 per 1,000). The reasons for the disparity are still unclear.

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Thirty years ago - The chances of having twins are higher today than they were 30 years ago. Experts believe the reason is that more women are choosing to have children later in their life. The birth rate of twins has increased 76% since 1980.

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Mother's age - Indeed, a woman is more likely to bear twins the older she is, say in her early 30s rather than in her mid-20s.

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DNA profile - While sharing identical DNA, identical twins do have physical characteristics that are quite unique to them as individuals: fingerprints! Fingerprint signatures can be distinguished from around the 10th week of fertilization.

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Partners in crime - In January 2009, jewelry worth $6,800 was stolen during a robbery in Berlin. Although wearing gloves, the perpetrator left behind beads of sweat at the scene of the crime. Police took DNA swabs and the results led them to two suspects, Hassan and Abbas, a pair of identical twins! It's never been established who the culprit was.

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Talking to each other - According to studies, around 40% of infant twins talk with each other in their own unique language. Only later do they learn to communicate properly with the rest of the world.

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Hearing - Another interesting statistic is that around 22% of identical twins are born deaf.

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Average weight - The average weight of infant twins at birth is anywhere between two and three kilos.

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Premature babies - Studies indicate that most moms carrying twins go into labor at 36 to 37 weeks, as opposed to 40 in a single pregnancy. However, if the twins are born after 34 weeks there should not be a major problem. more than 50% of twins' pregnancies occur before 37 weeks. In this sense, the pregnancy lasts less time than normal.

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One and the same - According to clinical psychologist Maria Elizabeth Barreto de Pinho Tavares, parents usually treat twins as if they were one person, by dressing the pair in the same style of clothes, for example. However, this can create identity issues later in their life.

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Fraternal twins - Women who are fraternal twins are more likely to have twin children.

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Different twins - Fraternal twins are not necessarily of the same sex, do not closely resemble each other, and may or may not share the same blood group.

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Dizygotic twins - Fraternal twins are “dizygotic,” meaning that they developed from two different eggs fertilized by two different sperm cells.

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Famous twins - Hollywood has some famous twins, such as sisters Mary-Kate and Ashley Olsen. The twins are two of the wealthiest celebrities in the movie industry.

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Twin siblings - Actor Ashton Kutcher has a twin brother - Michael Kutcher, who unfortunately was born with cerebral palsy.

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Brother and sister - Twins can be of different sexes as is the case with actress Scarlett Johansson, who has a twin brother - Hunter Johansson.

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Octuplets - The greatest number of babies born at the same time and to have survived is eight. Worldwide, only two groups of octuplets have survived beyond infancy, one in Texas in 1998 , the other in 2009 in California.

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How to tell twins apart - To tell twins apart, look at their belly buttons! Navels are scars from the detachment of the umbilical cord after birth. Monozygotic twins (maternal/identical) are by large of the same sex and can be born in separate months.

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