Random? I know but I just found out that the Mary-Kate and Ashley Olsen are fraternal and not identical. The Olsen twins look so much alike that I can't tell them apart. However, Tia and Tamara Mowry are identical but they don't look exactly the same. They look similar but look different at the sametime and it's so easy to tell them apart without looking at Tamara's mole.

So I don't understand how The Olsen twins are considered fraternal when they look pretty much exactly the same and the Mowry sisters are considered identical when they look kind of different?

It isn't based on how they look, but how they are conceived. Fraternal twins are when two different sperm enter two different eggs, forming two fetuses of different DNA. Identical twins are when (if I remember correctly) the twins have the exact same copy of DNA, because they were created by the same sperm and egg, the egg merely split in half after being fertilized. So, the twins aren't 'considered,' but simply are fraternal/identical, no matter if a fraternal set of twins looks more alike than an identical set.

TMI? :D

What Spiffy said. Also, perhaps you haven't seen the Olsen twins lately but they look pretty different now. One is taller than the other and they've done different things with their hair and such (Looking through pictures, one has a slightly longer chin and forehead which is easier to see now than when they were younger). They have very similar faces but so do some non-twin siblings. I think the reason you can tell Tia and Tamera apart well is because of their facial expressions. I was looking through some pictures and most of them I could tell who is who but in the ones where they were making the same facial expression it was very hard to tell.