- Identical vs. Fraternal twins
- Provides absolute certainty about the twins
Identical vs. Fraternal twins
A twin zygosity DNA test is used to determine whether twins, triplets or other form of multiples are identical or fraternal. At birth, the doctor can examine the placenta to make this determination; identical twins share a placenta while in utero, while fraternal twins do not.
A twin DNA test provides absolute certainty about the twins’ relationship, which is helpful when a doctor is unable to make a conclusive determination, or if parents have questions about their children as they age. For example, twins thought to be fraternal at birth may grow up to look identical. Conversely, twins thought to be identical may grow up to look very different. A DNA test can provide absolute confirmation that the children are either fraternal or identical.
Identical twins come from the same zygote, or fertilized egg. The zygote splits to form two or more embryos, and as a result, identical twins share the same DNA. Fraternal twins develop when two eggs are fertilized by two sperm, which means their DNA will be different. During a twin zygosity DNA test, the twins’ DNA samples will be compared. If the DNA is identical, the twins are determined to be identical. If the DNA shares similarities but is not identical, much like regular siblings, the twins are determined to be fraternal.
A twin zygosity DNA test can be performed any time after the children are born. DNA samples are collected from each child using a buccal (cheek) swab, which is done with a cotton swab swiped across the inside of one’s cheek. DNA is extracted from the collected cells in a laboratory and then is compared.
Turnaround Time: Approximately 10 Business Days Price $249.00 plus tax
“DNA may also be collected through other means. Common forensic samples are hair (must have the root ball attached), mucous on a tissue, earwax and toothbrushes. However the cost will be on average $125 extra.”