Special Instances of Birth:

We want to look at twins for the sake of this topic. This is when one mother gives birth to two babies at the same time.

Multi births occur when more than one egg is fertilized and implanted in the uterus. It can also be due to cell division. We will talk about identical twin, fraternal twin (non identical) and Siamese

Identical twins

This is a uniform development. It is also known as the homozygous twins. These type of twins are formed when one egg fertilized by a sperm. The zygote splits into two new separate cells before implantation (pregnancy). These two separate cells will each develop into separate embryo. These embryos form twins that are identical because they are formed from the same egg. It is very hard to tell the babies apart once they are born.

Fraternal Twins (Non – Identical)

These are twins formed from different eggs. They are formed as a result of fertilization of two eggs which are released at the same time from two ovaries by two different sperms. They develop separately in the uterus and this makes them share different placenta. They are just like two babies born by the same mother. Since the two separate eggs are fertilized by two different sperm the zygote ends up having different characteristics and appearances but may carry similar resemblances due to the sperm and eggs coming from the same mother and father. But the resemblances between identical twins are far more evident as compared to fraternal twins (non-identical twin)

Siamese twin

These are identical twins formed when a fertilized egg fails to divide and separate completely into two during development. The babies formed will be joined at a common point such as head. Stomach, etc. and they share some important organs due to this. Some Siamese twins are separated through surgical operations and they live to grow but others die through these surgical operations.