If you are a twin, over the course of your life, you will inevitably be asked many times whether you are identical or fraternal. Christa and I have always told people we are fraternal because that is what was told to us since we were small.
Identical twins form from one sperm and one egg. The sperm fertilizes the egg and then the egg splits into two eggs. Identical twins share identical DNA. Fraternal twins form from two different eggs and two different sperm. Fraternal twins have different DNA.
So where does the third twin come into play?
For years when Christa and I told people we were fraternal twins, they often did not believe us. They felt that since we looked just alike (we go through phases where sometimes we look more alike that others) and talked the same, we must be identical. We clearly looked a lot more similar to each other compared to our older siblings.
A few years ago someone told Christa about a “third twin” that had been discovered. The term is referred to as “semi-identical” and can be characterized by one egg and two sperm. Semi-identical twins have identical DNA on the mother’s side, but share 1/2 of the father’s DNA.
According to Time Magazine, Semi-identical twins are rare and the science is new compared to what we know about identical and fraternal twins. Semi-identical twins could form from 2 possibly scenarios. In the first scenario, 2 sperm fertilize one egg and then the separation is divided within one egg. The second scenario (the one that is much more likely) occurs when two sperm fertilize one egg and then at the second stage cell, each side sheds the chromosomes from each sperm.
Christa and I are not sure that we are the third type of twin, but we think it could be a possibility. It would explain why we seem so much more similar than most fraternal twins. Here are some of the eerie similarities that we have in common, but our other siblings don’t have.
1. We both have cysts on our heads.
2. We both have had thyroid issues (Christa- thyroid cancer, me growths on my thyroid).
3. We both have had polyps.
4. We’ve been known to show up wearing the same outfit without talking to each other beforehand!
I always wanted to have twins because I wanted several kids, but did not like being pregnant. My doctor would always tell me he was not going to do anything to help me have twins because it was a higher risk pregnancy. When Christa (who is a twin) got pregnant from Brad (who is a twin), they initially had what is called a “vanishing twin”. Charlotte started out as a twin, but quickly into the pregnancy the other sac went away.
Brad’s mom thinks that there is a good possibility that Brad and his twin brother Brian are identical twins. If they are not, then they would definitely have a chance of being the third type of twin!
One day our goal is to make it to the annual Twins Days Festival in Twinsburg, Ohio. This year the festival is celebrating its 40th anniversary and will be held from Saturday, August 8th to Sunday, August 9th.