What is a Twin Study?
Twins, also known as twins, refer to the situation where a viviparous animal gives birth to two individuals at one time. Twins can generally be divided into two categories: identical twins and fraternal twins. Identical twins refer to the development of two fetuses from one fertilized egg, and fraternal twins develop from different fertilized eggs. The average birth rate for twins worldwide is 1:89.
- Fred & George-From Harry Potter