Difference between monozygotic and dizygotic twins
Difference Between Monozygotic and Dizygotic Twins

4 Difference Between Monozygotic and Dizygotic Twins

The main difference between monozygotic and Dizygotic twins is that monozygotic twins are identical because they thrive from one zygote whereas the Dizygotic twins are not identical because they develop from two separate zygotes.

Twins are two children produced in the same pregnancy. Therefore, they can be monozygotic (identical) or dizygotic (fraternity). The family with the history of twin siblings has a higher chance of making more twin brothers than the family without the twins.

That’s because fraternal twins are hereditary while identical twins are not. The fraternal twins are produced by genes located on the X chromosome. Therefore, if a man has twin brothers in his family, he can pass on the twin genes to his daughter.

A woman generally releases one ovum each month. The ovum is produced from the process called oogenesis.

If the ovum is fertilized properly by the spe^^rm cell, then each ovum will develop into an embryo in the uterus.

In some cases, women can release more than one ovum in each month. After the conception, each zygote will be subjected to cleavage.

After splitting, each zygote will live in two different pockets. This is what caused a twin pregnancy.

Twin pregnancy factors

Before discussing the Difference Between Monozygotic and Dizygotic Twins, we first discuss the twin pregnancy factors.

There are several factors that can influence the occurrence of multiple pregnancies, such as the following.


Women over 35 years old tend to emit more than one egg follicle when ovulation. The increasing production of the ovum is influenced by the number of FSH hormones in women of these ages rather than younger women.


Twins (fraternal twins) can be inherited from the mother’s side. If a woman has a mother’s lineage or a grandmother who has twins is not identical, then the chance of the woman to experience a twin pregnancy will be greater.

In Vitro Fertilization Methods (IVF)

A person undergoing an in vitro fertilization program also has the opportunity to experience a higher twin pregnancy. It is because when the IVF program is done, the mother’s womb is planted by more than one embryo. The condition opens the chances that all embryos successfully grow and produce twins.

Read also: 6 Weeks Pregnant Symptoms

Difference Between Monozygotic and Dizygotic Twins

Monozygotic Twins


Monozygous twins: Twins are produced when one zygote is formed when the egg is fertilized by a spe**rm cell, but then produces two embryos that grow into two babies that have exactly the same (identical) properties.


Monozygotic twins always have the same genitals, unless there is a mutation in the development of one of the fetus.

In Monozygotic twins, the level of facial similarity is very high.

Babies with identical twins must have the same blood type.

Cause of occurrence

Monozygotic Twins (also called identical twins) occur when a single ovum is fertilized by a spe**rm cell and forms one zygote (monozigotic).

In its development, the zygote further divides into two different embryos.

Ovulation process

Both embryos evolved into mutually shared fetuses in the same womb. Depending on the stage of the separation of zygote, identical twins may share the same amnion (monoamniotic) or different amnion.

Identical twins instead of Monoamniotics can share the same placenta (known by monoorionic) or it can also not. All monoamniotic twins must be monocorionics.

Sharing the same amnion and the same placenta can cause complications in pregnancy. For example, the umbilical cord in monoamniotic twins can be twisted so as to reduce blood and nutrient delivery to the developing fetus.

The Dizygotic Twins


The dizygotic twins: twins were produced when two eggs were fertilized in two spe**rm cells, resulting in two zygotes growing into two babies with different properties.


The dizygotic twins are genetically no different from ordinary siblings and develop in separate amnion and placenta.

They can have different genders or alike. 

Fraternal twins can have different blood types

Cause of occurrence

The Dizygotic twins occur when there are more than one egg cells attached to the uterine wall which is fertilized by the spe**rm cells at the same time.

Ovulation process

In women, the ovulation process sometimes releases more than one mature egg to the Fallopian tubes which, when each is covered, will bring up more than one zygote.

Thank you very much for reading The Twins Pregnancy Factors and The Difference Between Monozygotic and Dizygotic Twins, hopefully useful.

Last Updated on June 13, 2020 Reviewed by Market Health Beauty Team

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