Scientists have found the second ever Semi-Identical twins in Australia.
There are three types of twins. The two most common twins that people are familiar with and whom scientists have become accustom to. The two most common are identical and fraternal twins. Identical twins occurs when a single fertilized egg splits into two and then forms two individual babies. Therefore, the identical twins share the same sperm and egg. Identical twins always have to be the same gender and their DNA will be 100% the same. The next common type of twins are called fraternal twins. Fraternal twins occur when two eggs are released and are fertilized by two different sperm. The fraternal twins can be either gender and they will share 50% DNA.
The third type of twins that is very rare is called semi-identical. In fact, scientists say that it is so rare that they have just discovered the second case in all of history to be semi-identical twins. The semi-identical twins are now four years old, but they have been determined to be semi-identical. The siblings share 100% of their mother's DNA, but then do not fully match their father's DNA.
Semi-Identical twins is when the siblings share 100% of their mother's DNA, but only share 50% of their father's DNA. Semi-Identical twins occur when one egg is fertilized by two different sperm. The egg then breaks into two and create two separate babies. Scientists say that this is so rare, because it just "shouldn't happen." If this does happen, the embryo shouldn't be able to survive. However, in these two cases, the embryos survived and created two sets of healthy twins.
The Australian twins are not newborns anymore, because the study took awhile. Scientists had to prove that these twins were actually not identical, or fraternal. The scientists had to prove that these twins actually shared more DNA then the typical fraternal twins, but they didn't share 100% of their DNA. This is a seriously insane finding. It just shows how amazing the human body is and really what it is capable of doing.