Fraternal twins are the most common type of twinning, also known as Dizygotic or Non-Identical Twins. By Kaitlin Reilly. Identical twins are also called monozygotic twins while fraternal twins are also called dizygotic twins. Fraternal twins develop when two different fertilized eggs implant in the uterus following conception. No, But Photographic Evidence Suggests Otherwise — PHOTOS. While the average person may not know th However, there are major differences in fraternal and identical twins. 15 Amazing Things People Don't Know About Identical VS. Fraternal Twins. Are Mary-Kate & Ashley Olsen Identical Twins? But scientists often like to compare identical and fraternal twins to understand how much variation in a trait is due to environment versus genetics. Some of them, like Rami Malek's twin, Sami Malek, are identical to their more-famous counterparts. Some of us may know what all the words in this sentence mean, but other may just recognize the word twins but wonder what the rest means. Fraternal twins, which are non-identical twins, are also referred to as dizygotic twins, biovular twins, dissimilar twins, and if both babies are female, they can be referred to as sororal twins. Why Fraternal Twins Run in Families. Identical and fraternal twins are two types of young produced by the same pregnancy in animals. This happens when two eggs have been released called hyperovulation, which are then fertilized independently, by two separate sperm. Huh? Fraternal and identical twins and genetics? When a woman finds out she is expecting twins, she may or may not know to ask what kind. We've rounded up 30 celebrities you probably had no idea were twins. Are Fraternal Twins Genetic?