7 unique facts about non-identical twins that surprise you

Twins don't have to have faces that look alike. Fraternal twins are twins that are not visible twins with the naked eye. Even the twins can be of different sexes, one female, and the twin male. Do you know the facts about twins are not identical?

1. It grows from different eggs and sperm

These fraternal twins or non-identical twins are different from identical twins. If identical twins come from the same egg and sperm (called monozygotic). Whereas fraternal twins come from different eggs and different sperm, this is called a dizygotic condition.

Generally, once ovulation, women release one egg, whether it's from the ovary (ovary) on the left or right. However, in pregnant women who have fraternal twins, not one but several eggs are released.

As a result, when sperm enter, different sperm swim to one of these eggs. Each egg is fertilized at the same time.

2. Derived from a different zygote

Because fraternal twins occur in different eggs and sperm, they grow and develop from different zygotes. Mothers who have twins will contain 2 zygote cells in the uterus.

The zygote is a cell that results from the union of sperm and ovum which form the embryo of the fetus in the uterus. Because they are different zygotes, non-identical twins have different physical conditions.

3. The gender can be different

Since non-identical twins come from different eggs and sperm, it is very possible if they are different genders. Fraternal twins can be the same as girl, same boy, as well as boy and girl.

What determines a male or female is influenced by the chromosomes carried by the sperm. Sperm can carry either an X or a Y chromosome, while women carry only one type, the X.

In the case of fraternal twins, when one egg is fertilized by a sperm carrying a Y chromosome, a boy will be formed. Meanwhile, if the sperm fertilizes the other egg by carrying the X chromosome, a daughter will be formed.

Therefore, fraternal twins can have different sexes, unlike children who are identical twins.

4. Have a much different physique and character

Like siblings in general, non-identical twins also have different shapes and traits.

From eye color, hair shape, height, to their character can also be very different. Because, they have different DNA, unlike identical twins who have the exact same DNA.

These non-identical twins are like siblings in general who have different birth years. Not always physically exactly the same, right?

Well, just like fraternal twins, the difference is that the two fraternal twins grow and develop at the same time, not in different years like younger siblings in general, with different years of birth.

5. Chances of having fraternal twins are genetic

Fraternal pregnancy occurs because there are 2 fertilized eggs at once. Because some women do have several eggs in one cycle, this condition is called hyperovulation. Women who frequently experience hyperovulation have the potential to experience these non-identical twin pregnancies.

This hyperovulation trait is genetic or hereditary. Women who have genes that cause hyperovulation can pass this trait on in their daughters to have fraternal multiple pregnancies again.

6. Have 2 different placentas

In contrast to identical twins in general, non-identical twins live in the mother's womb with their respective placentas, this is called dichorionic.

The placenta is an organ that functions to distribute oxygen and nutrients essential for growth and development in the womb. This organ is also a barrier for germs or foreign substances from the mother to enter the baby's body.

Because fraternal twins have different placentas, this pregnancy is not prone to the risks that often occur in identical twins. For example, the fetus is fighting for food and ultimately the supply of nutrients is not evenly distributed so that the umbilical cord is likely to become tangled easily which can interfere with fetal development.

7. Can form at different times

Usually during ovulation only one egg is released, but this is not the case for fraternal twins. Therefore, sometimes the zygote can form at different times, there are intervals.

For example, one egg was fertilized by sperm after sexual intercourse today, and another egg was fertilized during the next sexual intercourse. As a result, fraternal twins can have different gestational ages for several days. This phenomenon is known as superfetation.

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