A popular question for fun that gets bantered on the Facebook groups for parents of multiples is “Are my Twins Identical or Fraternal?” Then there is usually a great fun time where mums and dads post their photos of their twins or more for the community to play along and guess. I have played this game and honestly I did not know if my girls were identical or not. Some days, yes and other days no I was not sure.

When people ask why don’t I know, it is because both my girls had separate sacs which is the same as fraternal twins. This can happen when the egg splits very early (within 4 days). Essentially, the earlier the egg splits, the more independent each twin will be by having their own amnion, chorion and placenta.

About Twins

Just quickly if you are new to the Twin world. There are two types of twins – identical or monozygotic (one egg), and non-identical or dizygotic (two eggs) twins. Other names for identical twins are non-fraternal twins, and non-identical twins are sometimes called fraternal twins.

How do identical twins happen?

Identical twins form when one egg has been fertilized by one sperm and the zygote splits into two. This happens at the very earliest stage of development, when the zygote is no more than a cluster of a few cells. Dividing this early in conception means that each baby has exactly the same genetic information as the other.

So if you do not know if your twins or more are Identical or not, the best way is to order a DNA kit. This is a harmless test where you gently scrape the inside of each twins’ cheek with a little brush and post the samples back to the lab. It takes about two weeks where they extract the DNA and compare each DNA sample of a number of key markers to see if they are the same or different. I had wanted to do the test for years but it was always on the to list but finally I did it. I was excited to get the results today but the girls were a little, “meh” to say the least.

When I asked them what do they think they are – they responded as identical but not really sure what that meant. So I tried my best to record this BIG occasion! on video streaming, Periscope (follow me at @lisadlastdegree) – but they were not really in the mood to play along. So here is the BIG announcement! Enjoy! Note – if the video says not playable just try a different web browser.

Question to the community

How did you confirm your twins were Identical or Fraternal?”