Identical triplets?

I’m pretty sure twinning can occur even a little beyond the morula phase. In fact, I think it’s possible to tell roughly when the split occurred, because if it happened at or shortly after the zygote phase, one can see two fused chorions and placentas. If twinning took place later (say at the morula stage and beyond), there is a single chorion with no fusion, as well as a discrete placenta shared by both embryos/fetuses.

As I mentioned above, I’m pretty sure if twinning takes place late into the blastocyst phase, there’s high danger for them to be conjoined.

If they share a placenta, doesn’t that mean that they effectively ARE conjoned, since they share an organ?


Some vanishing twins are actually absorbed by the surviving twin! :eek: :eek: :eek:

There have even been identical quints. The Dionnes of Canada were identical, but the Diligentis of Argentina were fraternal. I’m sure that many, many more fraternal multiple births are being seen now due to fertility treatments.