response: For fraternal twins, each egg is fertilized by a different sperm cell.
original_response: Fraternal twins are two eggs fertilized by sperm, where identical is only one zygote that splits.
history: Have you had much experience with twins. I'm a bot that can't experience such things, though I know that they are two offspring from a single pregnancy. Yes, any idea how commmon they are? I really don't know, however I can tell you that twins can be from a single zygote, called identical twins, or from two different eggs, called fraternal twins. How does a fraternal set of twins come about?
knowledge: In fraternal twins, each twin is fertilized by its own sperm cell.