Twins can have different biological fathersIn 2009, Mia Washington gave birth to twins with two different fathers, a one-in-a-billion occurrence. One month, Mia released two eggs instead of one. Her two sexual partners each fertilized one of the eggs, resulting in two babies with two dads. In 2011, there were only 3 known cases of this occurrence.
In rare cases, twins can be different races.Although it may be hard to believe, Kian and Remee are twins. This is the result of a one in a million combination of their parents’ genes, who are mixed race. If parents are mixed race, their eggs or sperm contain the genetic code for both black and white skin and in very few cases this results in twins of different skin colors.
Separated twins can live eerily similar livesJim Lewis and Jim Springer were four weeks old when they were separated, with each of the twins going to different adoptive families. It was later discovered that their lives shared some truly remarkable similarities. Both had a dog named Toy as kids. Both married twice, first to women named Linda and second to women named Betty. Both drove Chevys, smoked Salem cigarettes, and drank Miller Lite.
If a pair of identical male twins marry a pair of identical female twins, their children will legally be cousins but genetically be full siblings.Two children are genetic siblings if the chromosomes both children received were derived from the same pool. Since the genetic pool of identical twins are identical, these two sets of parents would produce children from identical pools.
Source: USA Today
Women who give birth to twins may live longerWomen who give birth to twins are generally healthier and stronger to begin with than those who don’t. Some believe that twins are an evolutionary adaptation, where the healthiest of mothers take the chance to pass on double the genes at once.
Tall women are more likely to have twinsThe Long Island Jewish Medical Center discovered that taller women have more insulin-like growth factor (IGF) - a protein that increases a woman’s chance of ovulating. The more IGF a woman has, the greater the chance that she will become pregnant with twins. Other research found that women who gave birth to twins were on average one inch taller than other mothers.
Women who eat a lot of dairy are also more likely to have twinsA study in the Journal of Reproductive Medicine compared twin birth rates from vegan and non-vegan mothers. Those who consumed dairy were five times more likely to have twins. Cows, like humans, also produce IGF and release it into their milk, which the women consume.
Twins interact with each other in the wombThe University of Padova recently discovered that twins are as close in the womb as they are outside of it. At 14 weeks of gestation, twins were seen reaching for each other. Four weeks later, twins in the womb touched each other more often than they touched their own bodies. The twins were gentle to each other and made distinct gestures toward each other.
Twins that are exact reflections of each other are called Mirror Image TwinsAround 25% of identical twins develop directly facing each other, meaning they become exact reflections of each other. One is often left-handed, while the other is right-handed. They may also have birthmarks on the opposite sides of their bodies.
Some conjoined twins can hear each other’s thoughts and see through each other’s eyesKrista and Tatiana Hogan are attached at the head and share a thalamus - the part of the brain that controls physical sensations and motor functions. As a result, the girls can see through each other’s eyes and hear each other’s thoughts. They can also feel and see what the other one does.
A mother's body adjusts uniquely for twinsA mother's chest will heat up or cool down to regulate the temperature of a baby held on her chest. When a mother holds twins, each breast can independently adjust its own temperature to account for each child.
One of the easiest ways to tell identical twins apart is their belly buttonsBelly buttons are scars from the detachment of the umbilical cord, so they aren’t caused by genetics and each one is slightly unique.
A woman is more like to give birth to fraternal twins if she is one herself, has already given birth to fraternal twins or has a sibling who is a fraternal twin.
Identical twins do not have identical fingerprintsFingerprints are not solely shaped by DNA. Although they start with the same fingerprints, during weeks 6 to 13 of pregnancy, when the twins start to move, they touch the amniotic sac which forms unique ridges and lines.
Left-handedness is nearly twice as common in twins than in single individuals.
Twins can be born weeks or months apartAmy and Katie are twins that were born 87 days apart. Their mother's water broke a mere 23 weeks into pregnancy. Amy was born four months premature, weighing little more than one pound and fighting for her life in an incubator while Katie was struggling to survive in the womb. While not common, the previous record for separate births was 85 days.
Identical twins can make master criminalsApart from their fingerprints, identical twins are 99.99% identical on a DNA level. In January, 2009, $6.8 million worth of jewelry was stolen in Berlin. The single suspect (who was wearing gloves) left behind sweat beads, which police extracted DNA from and tracked down to two people - Hassan and Abbas O. - identical twins. Both denied responsibility, accused the other, and because police couldn’t identify which of the twins the DNA belonged to, both ended up walking free.