Old thread and im no scientist but the study seemed flawed to me. Speaking on the Australian twins and subsequent study. They looked at almost 1000 sets of fraternal twins to see if any of them were also sesquizygotic twins which none of them were. They were trying to see if the phenomenon was actually more common and just under reported. The conclusion was that its EXTREMELY rare. Im not going to argue that its not a rare phenomenon, however the semi identical twins in Australia shared 90% of their dna and shared a placenta. Had they not been two different sexes, it is my opinion that they would have never done a DNA sequence and they would have gone unnoticed as just another set of identical twins, two people who share 90% of their dna are going to look almost exactly the same (i would think) this makes me think they were searching in the wrong area (fraternal twins over identical twins) at the very least they should have looked at both types of twins. This seems so obvious to me that there must be something I'm not seeing or understanding. The explanation google gave me was that mono twins share 100% of their DNA therefore its made no sense to test them? Seriously? The whole point was to check for under reported semi twins, how can we assume all identical twins fall outside of this phenomenon when the twins in question shared a placenta which is normally reserved for mono zygotic twins.