The Science
Two Types of Twins
Twins are either identical or fraternal — the difference comes down to how they were formed at conception.
Identical (Monozygotic)
One Egg, One Sperm
Identical twins form when a single egg is fertilized by a single sperm, and the resulting embryo splits into two. Both twins develop from the same genetic material, resulting in identical DNA profiles.
Fraternal (Dizygotic)
Two Eggs, Two Sperm
Fraternal twins form when two separate eggs are fertilized by two different sperm cells at the same time. Each twin develops from a unique set of genetic material, resulting in different DNA profiles — just like any other siblings.
The Test
How We Determine Twin Type
DNA Profile Comparison
The test determines the complete DNA profiles of both twins. If the profiles are identical, the probability of being identical (monozygotic) twins is calculated and reported.
If the profiles differ — even at a single DNA locus — the twins are confirmed to be fraternal (dizygotic), sharing DNA only as typical biological siblings would.
Results in 3–5 working days