All Twins are Identicals?
Many people believe that twins are simply twins. But exist a difference.
We have 2 types of twins:
Identical twins —-do not run in families, but happen by chance . Identicals come from the same fertilized egg, and is also called monozygotic. This means that they share all the same genes and DNA, and this is why they can be so hard to tell apart. But their fingerprints are different . However they are not always exactly identical.
Immediately after birth they look similar, but over the years we start to observe some differences. The DNA sequence is identical, but epigenetic changes do not alter the DNA sequence, but can control the expression of the genes , due many environmental influences like what we eat, we drink, we inhale, which environmental we live and so on. Twins do not have exactly the same lifestyle and do not live in the exact same environment for their whole lives. Exposures can change the epigenetic patterns of all tissues in their bodies. The consequences of these changes are alterations in gene expression. This is why over time, identical twins do not only look different, they actually have become biologically different as well.
How can they come from the same egg?
Sometimes before the 8th day after the egg and sperm meet, the fertilized egg splits into two. Then these two halves grow into identical babies. Ovulation is a normal biological process that is controlled by our genes. Different women have different versions of these ovulation genes. Some women have versions of these genes (called alleles) that make them more likely to hyperovulate. Embryo splitting, on the other hand, occur randomly by chance. Identical twins are random and genes are not involved. One theory is that hormones play an important role. The hormone FSH follicle-stimulating hormone may be higher in mothers of twins. FSH is necessary for egg growth and normally is used as a fertility drug.
Fraternal Twins —-can run in the family. This happen by mom releasing two eggs, and the dad’s side of the family doesn’t come into play. Fraternal come from two different eggs, and are also called dizygotic. They are really like any two siblings who happen to be born at the same time. With fraternal twins the mom releases more than one egg at a time, she ovulates more than once per menstrual cycle. Twins result from two eggs getting fertilized and growing in the uterus at the same time. Because they come from different sperm-egg pairs, they don’t look any more alike than any other siblings. This explains why half of fraternal babies are a boy and a girl. Imagine that your genes can affect whether you have fraternal twins, because genes are involved into the ovulation process.
The genes versions that increase the chance of hyperovulation can be passed down from parent to child.
This is why fraternal twins run in families. This is why having a background of twins in the family matters only if it is on the mother’s side.The genes that cause a woman to have fraternal babies is unknown. Mothers of fraternal tend to be taller, and have earlier and shorter menstrual cycles. This occurs perhaps due to higher hormone levels.
Having two is more common now than it was in the past. According to the Center for Disease Control and Prevention, twin births have doubled over the last 40 years. A woman has a higher chance of having two with the assistance of fertility treatment or is aged 35 years or over.
How Twin Pregnancies Happen:
For the science until now, is not fully understand the reasons why twin pregnancies occur. Some factors can increase the likelihood of giving birth to two, such as :
- the woman’s age
- family history of twins
- fertility treatments
- obesity
Age —Woman who are aged 30 years or older are more likely to conceive two, because she is more likely than younger woman, to release more than one egg, during their reproductive cycle. If sperm fertilizes two separated eggs in the same time, a twin pregnancy can happen.
Family history —A family history of twins on the mother’s side increases the chance much more, than the father’s side. However, this works only if conception takes place without the fertility treatments. Women who are themselves nonidentical babies, produce twins in around 1 to 60 births. For men who are nonidentical twin, the chance is less, 1 to 125 births. People believe that twins can skip a generation, which means that one of their grandparents did, their chance increase.
Fertility treatments —Some fertility drugs work by stimulating a woman’s ovaries, which can cause them to release more than one egg. and if sperm fertilizes both of these eggs, this can result in two or triplets.
Fertility treatments increase the chances of having two. However a twin pregnancy is riskier for both the woman and the developing foetus. A twin pregnancy increases the risk of low birth weight, premature birth, diabetes during pregnancy, cesarean delivery, needing bed rest while pregnant and so.
Fertilization in Vitro (IVF) can also increase the chance of conceiving twins. This method works by extracting a woman’s eggs and fertilizing them with a donor’s sperm, and then transfer the embryo into the woman’s womb.
Height and obesity —Fraternal twins is more common in taller or heavier women than they are in small women. The reason is not clear, but may be due to better nutrition. Women with higher body weight may have more resources for a developing foetus.
There is no way to improve the odds of having twins naturally !
by Helena
Naturalize Yourself !
