Identical or Fraternal? For many twins, that is the question! Whether you want to know the answer to this question with 99% accuracy from a clinical zygosity test, or are just curious to know what type of zygosities are out there, look no further!

To learn more about the types of zygosity including identical, mirror-image identical, fraternal, and half-identical twins click on the "Zygosity Facts" button below.

To see what labs can conduct zygosity tests to determine whether twins are identical or fraternal, click on the "Zygosity Testing" button below.