ELI5 Twins - why do identical twins have different fingerprints?

What is a half twin? If twins have identical DNA, how come their fingerprints are different? If identical twins have kids with another set of identical twins, are their offspring technically brothers or sisters? If two twin brothers are disputing to see who is the father of a child, can science determine which of the two is the real father? Why are there so many twins in hollywood? Does face scanning recognize twins as the same? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: minigirl17, sterlingphoenix, whoisxu, babybopp, chasedonovan, michelkz, backwardslion, uscmissinglink, idiotmanchild, cardboardunderwear, ehh22, agitaive_auto, matrozi and mjmurcott. To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]