uh.... they(fraternal & identical) usually have the same birthday! fraternal twins don't share one sac in the mother's womb, so they each lay in separate sacs. But they can sometimes have same characteristics.
I am a registered nurse...perhaps I can answer you. Identical twins come from the same egg and the same sperm which has split after fertilization. They are known as monozygotic twins. Their DNA and fingerprints will be the same. they will have the same blood type and of course will be the same gender. Inside the womb, they shared the same amniotic sac and the same placenta. Sometimes they may be joined and then they are called Siamese twins. Fraternal twins come from 2 different eggs and they will have separate amniotic sacs and a separate placenta. These are known as dizygotic twins. Their DNA will be different so blood type. gender and other characteristics will also be different. The may be as different or as alike as any other sibling.Hope this helps.
My 4yo twins, boy and girl are just delightful, very different in personality, he's just taller than her, she has a little more asian showing through in skin tones, both clever, active and funny. Mind you, 10 people have asked us if they are identical lol... I just remind them he has the extra bit.