What are the different types of twins?
1. Identical Twins
2. Fraternal Twins
3. Siamese Twins
4. Mirror Image Twins
The main types of twins that everyone knows and talks about are Identical Twins (monozygotic) and Fraternal Twins (dizygotic). What most people don't know is that it goes much deeper than that. There are many different types of identical twins! Even twins in different sacs with different placentas can be identical. Both of my sets of twins are fraternal, but when I was going through my pregnanicies, I was surprised to find that sometimes not even doctors and ultrasound techs are aware of this fact.
The type of twins totally depends on how many egg and sperm are involved and when the egg splits.
Identical twins occur when one egg is fertilized by one sperm and then the egg splits. Identical twins may look exactly alike to most people. But their mother's may think that they look nothing alike. They can also be different based on weight and environmental factors.
Fraternal twins usually occur when two eggs are fertilized by two sperm at the same time. The two eggs form two zygotes. Fraternal twins can be two boys, two girls, or a boy and a girl – this is the most common form of fraternal twins.
(page being updated with more info soon)