Show Details

Identical Triplets

October 9, 2017

A listener asks if identical triplets are possible.



Three of a kind. I’m Bob Hirshon and this is Science Update.

Science Update listener Michael Mikkalo of Washington, DC wrote to ask if multiple births can result in identical triplets. We asked clinical geneticist Carol Greene of the University of Maryland Medical Center.

CAROL GREENE (University of Maryland Medical Center):

Yes, in the same way that there are identical twins, we can have identical triplets. Once you have fertilization, we have what we call a zygote, and if the zygote splits, you can have two identical individuals, and that would be identical twins. And if there’s another split then you could have identical triplets.


This is very rare, accounting for only about 10% of all triplets born. Even more rare are identical quadruplets, resulting from a further splitting of the zygote. And if you have a science question, give us a call at 1-800-whyisit. If we use it on the air, we’ll send you a Science Update mug. I’m Bob Hirshon, for AAAS, the science society.

Story by Science Update staff