For girl multiples, you can support them by reassuring your girls that periods starting at different times is perfectly normal. Some multiples have started their period three years before their twin/triplet.
"Twins married to twins who both have babies at the same time." Since identical twins share the same DNA, the children of two pairs of identical twins are legally cousins, but genetically more similar to siblings.
Most twins, triplets and more grow and develop along roughly the same lines as their singleton peers – even those who start out much smaller will catch up in time. But there is nothing to say twins, triplets or more have to reach milestones at the same time as each other.
It is likely that twins' awareness of one another starts sooner than seven or eight months of age. An article by the late doctor, T. Berry Brazelton, observed that at age three to four months, an infant identical female twin seemed disoriented when her sister was removed from the room.
At three months:
The three-month stage marks the end of the “fourth trimester” and your twins can better adapt to life outside the womb. For one thing, they'll sleep in longer stretches of about three- to four-hour chunks.
Monoamniotic-monochorionic Twins
This is the rarest type of twin, and it means a riskier pregnancy as the babies can get tangled in their own umbilical cords.
Identical twins live longer, possibly because they have a BFF from birth, according to researchers from the University of Washington, Seattle, WA. Furthermore, this effect is greatest in male identical twins, according to results from their recent study, published in the journal PLOS ONE.
The DNA of monozygotic twins tends not to be 100% identical, and epigenetic and environmental differences further widen the gap between twin pairs. It's not nature or nurture; it's a complex interaction between our genes, our environment, and our epigenetic markers that shape who we are and what illnesses befall us.
But any forensics expert will tell you that there is at least one surefire way to tell them apart: identical twins do not have matching fingerprints. Like physical appearance and personality, fingerprints are largely shaped by a persons DNA and by a variety of environmental forces.
With identical twins, it's possible for a blood vessel in a shared placenta to result in one baby receiving too much blood and the other too little. This is a serious complication for both babies that might result in heart complications and the need for fetal procedures while you're still pregnant.
When a twin dies, the twinless twin longs to reconnect. The twinless twin may have phantom pain or feel half dead. He or she may feel a need to represent both him or herself and the deceased twin or may even take on behaviors of the deceased twin.
At age 7, the mean IQ score of twins was 5.3 points lower than that of singletons in the same family, and at age 9, the score was 6.0 points lower. The lower intelligence of twins in childhood may partly be a consequence of the reduced fetal growth and shorter gestations of twins, say the authors.
Analyses of data from the National Longitudinal Study of Adolescent to Adult Health show that MZ twins were significantly more physically attractive and healthier than dizygotic (DZ) twins and singletons.
Identical twins are completely random. It's not based on family history or genetics. Identical twins form when a single fertilized egg splits and forms two embryos. Now in this case, it's not because of mom or dad.
In 99.9% of cases boy/girl twins are non-identical. However, in some extremely rare cases resulting from a genetic mutation, identical twins from an egg and sperm which began as male (XY) can develop into a male / female pair.
In Tetrick's case, doctors say it took a very rare chain of events. Two different eggs from Tetrick were fertilized — resulting in fraternal twins. Then those two separate eggs both split — resulting in two sets of identical twins.
According to the Guinness World Records, the longest interval between the birth of twins is 90 days. 5 The former record was 87 days apart for two sisters born in 2012—who, ironically, were born in Waterford, Ireland.
Identical twins share a particularly intense bond. They are the result of one fertilized egg splitting into two, giving them identical DNA. (Fraternal twins are the result of two separate, genetically different fertilized eggs.) As a result, identical twins are as close as two people can be.
The researchers determined a 96% chance that if one twin has ASD, the other has it, too. However, symptom scores varied greatly between twins diagnosed with ASD. The researchers estimated that genetic factors contributed to only 9% of the cause of trait variation among these twins.
Some identical twins can have different heights and weights. This is because height and weight are controlled by what you eat as well your DNA. Differences in diet can start earlier than you might imagine. When the twins are growing inside the uterus, there can be differences in how well they connect to the placenta.
It's a common misconception that twins skip a generation in families. There is absolutely no evidence, other than circumstantial, that twins are more likely to occur every other generation.
Environmental Differences
While identical twins form with the same set of genes, human development is not just genetic. The environment also has an impact. 1 So, beginning in the early environment of the womb, external influences can change the appearance of twins. For example, some monozygotic twins share a placenta.
Rosanoff ( 12-15), by a mass study of a large number of twins has shown that with a few exceptions, such as Huntington's chorea, this is not the case. In so far as the common types of mental ab- normalities are concerned, identical twins may or may not develop the same disorder.
A twinless twin, or lone twin, is a person whose twin has died.
Doctors called these cases vanishing twins or vanishing twin syndrome (VTS). The tissue from a vanishing twin is mostly reabsorbed by the mother's body and the remaining baby. Sometimes some evidence remains.