Â· 4 years ago. A mutation is a change in the genetic material of an organism. We are made from trillions of cells, each with a nucleus composed of DNA â a set of instructions that tells the cell what to do. Cells copy themselves with astonishing accuracy, but every now and then a piece of code is copied incorrectly.
Identical (or monozygotic) twins happen when a fertilized egg splits into two separate babies-usually within the first twelve days of Mom's pregnancy. After twelve days, the egg may not split entirely and result in conjoined twins.
During my sister's first pregnancy, she went to the hospital bc she had an mc. But it wasn't until then that she found out she was pg with twins and only lost one of them! Turns out she ovulates two eggs each month and there is a good chance she could get preg with twins every time.