In Mary-Kate and Ashley Olsen, we have a good example of fraternal twins who are different from each other in significant ways - which, if we look carefully, may betray their pre-birth origins as a set of multiple embryos. They were so similar as very young children that they were able to play the same role interchangeably in Full House.
The directors and producers of Full House did not want people to know that Michelle was played by a set of twins, so the girls were credited as Mary-Kate Ashley Olsen for most of the show's run. It wasn't until the final season that they were credited Mary-Kate and Ashley Olsen. Despite the fact that the Olsens are fraternal twins, their physical appearances were nonetheless similar enough so that few could tell the difference between the two.....This from Squidoo:
Many of these things listed below were used to tell them apart when they were younger. Some can still be used now to tell them apart.
- Mary-Kate is left-handed. Ashley is right-handed.
- Ashley is a little bit taller than Mary-Kate.
- Ashely has a freckle above her lip
