“Did you know, not all twins are identical and grow together in womb? Met twins or triplets look completely different from each other! Well,they are fraternal babies.
Fraternal twins or non-identical twins are just like any brother and sisters of a family with same biological parents. The only difference is that they are conceived at the same time, in the same month and share their mother’s uterus during same pregnancy.
But then identical twins go through similar phase!Well, here are some interesting facts about fraternal twins you may not have heard before.
Interesting Facts About Fraternal Twins You May Want To Know
1. Fraternal Twins are Formed By Two Separate Eggs
This term is known as Dizygotic where embryos are developed by two separate eggs and sperms. Identical twins are developed by one sperm and one fertilised egg which is later split into two embryos. Identical twins are called Monozygotic.
2. There are Several Factors That Influence Fraternal Twinning
Today’s lifestyle has drastically changed. Medication, heredity, diet, maternal age, BMI and number of previous children are some of factors that are associated to fraternal twins. These factors encourage Hyper-ovulation, aoccurrence where two eggs are released per cycle thusly increasing the chances of twins.
3. Fraternal Twins May Have Conceived At Different Times
This term is called Superfetation. Usually one egg is released during ovulation. However, in case of hyper ovulation, 2 or more eggs are released in interval of few days. Therefore, when one egg is fertilised and begins to proceed to the uterus, another egg can also be fertilised by sperm from a later date of sexual intercourse and can begin its travel for implantation.
Or By Different Fathers As Well…
There are also chances of fraternal twins being conceived by different fathers. This happens when a hyper ovulating woman has sexual intercourse with more than one partner at different time. This phenomenon is termed as Superfecundation.
4. Most Fraternal Twins Don’t Look and Act Alike
Identical twins since are produced from the same egg and sperm often have remarkably similar features, habits, personalities and choices.
However, fraternal twins are more like siblings from the same biological parents but born at the same time. They may look and act completely different from each other, including body type, hair colour, voice, height, weight, personality, habits and even characteristics.
No one can identify them as twins unless they say it aloud.
5. Fraternal Twins May Have Different Genders
Since both conceptions happen at different time intervals (most of the time), the twins can be of different genders, unlike identical twins. This is because the chromosome of father’s sperms that fertilise the eggs may not always be of the same gender (XX for a girl and XY for a boy).
In case of identical twins since a single sperm determines the gender, they would be either 2 XXs or 2 XYs.
6. Fraternal Twins Have Two Placentas
The placenta provides all the nutrition the baby needs from the mother to grow. In case of fraternal twins, each placenta develops a baby. However, it may get glued together and look like a single placenta. Therefore at times a scan may not determine the zygosity of the utero.
But unlike identical twins, where they share one placenta which poses certain risks to the babies such as Twin-Twin Transfusion Syndrome (TTTS) or Mono amniotic Twins, fraternal twins do not suffer any kind of risk.
7. Fraternal Twins Rates Vary In Each Country
In some countries fraternal twins are rated low, whereas the rate is abundant in other countries. For example, most fraternal twins’ population was found in Central African Countries, especially Benin. On the other hand Asia and Latin American countries had the lowest rate of twinning (2012 report).
8. Fertility Treatments Can Also Cause Fraternal Twins
The advent of medical technology in fertility enhancement treatments, have resulted in multiple births increasing in manifolds. Fertility treatments including IVF (in-vitro fertilization) and certain drugs often times produce multiple fertilisation with most births being Dizygotic.
9. Heredity Can Also Impact The Chances of Fraternal Twins
Like we have seen identical twins in each generation, fraternal twins can also run in the family. The tendency of Hyper ovulation could be a genetic trait.
Hyperovulation is a medical term where a woman releases multiple eggs from ovaries in each ovulating cycle. These women have more chances of conceiving fraternal babies. And this phenomenon could be passed on by mothers to daughters.
10. Fraternal Twins Will Share Only 50% of Their Parents DNA
Identical twins have perfect DNA match. However, like any other siblings or two off springs, fraternal twins will share 50% of their parents’ DNA (half from their mother’s egg and other half from their father’s sperm). That’s why they would have some overlapping qualities.