Indentical or Fraternal Twins ~ What is the Difference?
I get asked all the time if my boys are indentical or fraternal and then I get asked what the difference is, here is a quick lesson in twin basics. There are other catagories associated with twins but I'll just discuss these for now.
Identical Twins (or more formally known as monozygotic) occur when one egg is fertilized by one sperm and then the egg splits into two embryos. They will have the same blood type, eye color, gender and DNA.
Fraternal Twins (known as dizygotic) occur when two eggs are each fertilized by a different sperm creating two babies. These twins are no more genetically alike than any other brother or sister they just happen to be wombmates :)
Aside from obvious physical differences -- such as one baby being male and one being female -- it can sometimes be difficult for parents to know if their babies are identical or not. If they look the same, have the same eye color and are the same sex then genetics testing may need to be done to determine if they are identical or not.
I suspected my boys were fraternial but as soon as they were born I knew for sure. Their facial features were different, their heads were shaped differently, their body types were different, even their little baby foot prints were different. Strangers would come up and say -- "they look EXACTLY alike, it's remarkable really." and I would just chuckle to myself because I knew how different they really were :) Don't get me wrong, they do look like brothers just not like what most people would think of when they hear the word "twins." One of my boys has consistantly always been 2 inches taller than his brother which is confusing to people but as soon as I explain what fraternal twins are they understand :)