What’s The Difference Between Identical And Fraternal Twins?
The news that she`s about the give birth to twins might constitute a reason for joy for the young mother, but at the very same time may constitute a reason to worry when thinking about the way she`ll be able to handle more than one child at once. Suddenly, all worries seem to double, and bring two children at the same time to this world seem to be a double challenge.
Eventually, we`ll be able to understand more about twins and we`ll find out how we`ll be able to take care of them, the information being the same when having triplets or even more children.
Table of Contents
Identical Twins (Monozygotic)
- Monozygotic twins, also known as identical twins, occur when one single spermatozoid fertilizes an egg which in the initial development stages splits into 2 parts, each of them giving birth to one embryo.
- Identical twins have the same genetic code, and also the same sex.
- Some of the identical twins have their own placenta and amniotic sac in the uterus, while other ones share their amniotic sac and placenta with their brothers.
- Identical twins might have distinct weights at birth, but they soon begin to look the same, so that at some point their distinction becomes almost impossible.
- Identical twins don`t occur due to a result of parental genetic tendencies to give birth to twin pregnancies, the reason for which the embryo splits in the initial stages isn`t known.
- Monozygotic twins occur once every 250 pregnancies.
Non-Identical Twins (Fraternal or Dizygotic)
- They are also known as dizygotic or fraternal twins, and they occur from 2 distinct eggs that are fertilized by distinct spermatozoids, so that even from the moment of fertilization there are 2 different embryos that occur.
- Each of the embryos develops in their own placenta and amniotic sac. Also, each twin has its own place inside the uterus.
- Non-identical twins might be of distinct gender or might have the same sex.
- Non-identical twins are often similar at birth, but in time they begin to look less alike.
- The chances of occurrence of non-identical twins are much higher when there`s a history of twin pregnancies in the family of the mother or when the mother has followed a fertilization treatment in her attempt to conceive. If the mother was born from a twin pregnancy, chances of giving birth to twins are of around 10%. By comparison, for mothers who weren`t born from twin pregnancies, chances are of only 5%. On the other hand, the affiliation of the father to a twin pregnancy doesn`t seem to have any effect on the chances of having a twin pregnancy.
- Every 100 births, 2 are twin pregnancies with non-identical twins. With the growing number of women who turn to fertilization treatments, the incidence of twin pregnancies with non-identical twins has increased.
Siamese Twins (Conjoined)
- These twins are extremely rare and are known medically as conjoined twins.
- Siamese twins occur from the same egg that doesn`t separate totally in its initial stages of embryogenesis.
- Following an incomplete separation is the persistence of a specific structure which unites the twins; some of these twins may be separated through surgical intervention, but if the most important organs of the twins are common, the chances of survival to a separation are minimal.
Pregnancy that Seems Gemelar
With the progress of technology and ultrasounds, it could be seen more pregnancies that was originally thought to start as twin pregnancies – around 5% of all pregnancies in the week 12 are twin pregnancies, but as the pregnancy evolves one of the twins cease to develop, while the other twin develops quite healthy.
How to Find Out If There Are Monozygotic or Dizygotic Twins?
The doctor can find out soon after birth if the twins are identical or not. If their sexes are different, we are definitely talking about non-identical twins. Moreover, identical twins have certain health issues at birth, and throughout life, they may suffer lots of medical conditions. Even if the twins are non-identical at birth, we cannot know for sure they are non-identical; this can be established an obstetrician examines the placenta and performs several blood tests. – Click here!
Truths about Twins
- The term “twins” comes from ancient times.
- In ancient times, the birth of twins was interpreted as a divine sign. This is also the reason for which there are many twin gods, even when talking about different religions.
- Chances to have fraternal twins: 12 to 1.000.
- Chances to have identical twins: 4 to 1.000.
- Twins are more frequent in Afro-Americans and quite rare in Asians.
- Women with a twin brother have 5 times more chances to have twins on their own.
- Women who gave birth to twins have 4 times more chances to have twins in a future pregnancy.
- More than half of all twins are generally men.
- Of all twins, it seems that girls will stay closer throughout life.
- When developing all sorts of phobias, like fear of closed spaces, height, etc – twin brothers frequently respond in the same way. If one of them will feel an unjustified fear, the other one will feel the same.
Did You Know?
Scientists have also introduced the notion of twins with “polar bodies.” They occur when the mother`s egg splits before fertilization, and each half is seeded by a different spermatozoid. This is how it`s explained why some fraternal twins look like they are exactly the same.