Polar Body Twins
There is a third type that people call half-identical or polar body twins. Doctors say that this could explain why certain fraternal twins still look identical, but it has yet to be proven. An egg can split into two after its release, and the smaller one is known as a polar body. It can allegedly develop into a fetus if fertilized, but there is often too little fluid inside it for it to grow big and survive. If it survives, a sperm be fertilized by a sperm while the other half is fertilized by a different one. This is how polar twins are believed to be born. They come from one egg, so the chromosomes from the mother will be identical. However, they do not share chromosomes from the father. They are not necessarily the same sex.
Polar Body Twins
