When someone wants to know a little more about the twins they’ll often ask if they are Identical or Fraternal. Growing up with twin sisters, I answered this question quite often – my sisters are Fraternal which is when two different eggs meet two different sperm and two babies grow in their own sac. Whereas Identical twins split from the same egg after it has been fertilized by one sperm and either share the same sac or develop in two different sacs – but they are identical in every way.
It wasn’t until I had my own twins (also fraternal) that I realized how confusing this concept was for other people. On more than one occasion we have been asked if our boy and girl twins are identical which is impossible as the name “identical” suggests. Once we were even asked if they were siamese which led to a week long obsession singing the song from Lady and the Tramp.
However, in Costa Rica when they ask if I have twins, they ask specifically if they developed in one sac/identical (Gemelos) or two sacs/fraternal (Mellizos). At first I only picked up on the word Gemelos (pronounced er-mel-os) so I assumed it simply meant “twin” and would answer “Yes, a boy and a girl”. This would create confusion as I was essentially saying “Yes, they are identical, a boy and a girl” (see paragraph above on how that is IMPOSSIBLE).
Only recently were the two words explained to me and it made me better understand the complexity and confusion many people have around the concept of twins. Hopefully I offered a similar explanation (with patience) to those who have asked if my boy and girl were identical and thankfully I didn’t outright mock the person who asked if they were siamese…. who clearly skipped one too many biology classes and/or Disney films.