Twin Zygosity Testing

Curious whether your twin and you are identical (monozygotic) or fraternal (dizygotic)? Our twin zygosity testing can answer that question.

Identical twins are formed when one egg is fertilized by a single sperm cell and then divides within the first few days of pregnancy. Twins produced by this process are referred to as identical since their DNA sequence is identical. Fraternal twins are formed when two eggs are independently fertilized by two sperm cells. Fraternal twins do not have identical DNA but will have half of their DNA in common, just like siblings of the same parents that are born at different times. Fraternal twins can either be of the same sex or different sex.

The sample is collected by a simple mouth swab on the inside of the cheek.

There are two types of DNA tests available: legal and private. Our fully accredited laboratory follows the same rigorous high quality standards when processing both legal and private cases; the only difference is in the documentation procedures at the time of collection.

Legal, court-admissible cases require a chain of custody of the sample, which must be drawn from an approved Canadian DNA Services collection site. When DNA test results will be used for legal purposes, such as child support, social security, or custody matters, Legal DNA tests are required. Legal testing requires scheduling a collection appointment.

Private DNA tests provide the same information as a legal DNA test; but they are not intended for use in a court of law and are not considered court-admissible. They do not have special collection requirements and can be collected in the privacy of your home.

If you need a legal DNA test done, you can choose to come into one of our convenient testing locations across Canada or have a mobile unit sent to your home or work. During the collection process, the individuals tested are positively identified through photographs and government-issued identification. Certified DNA specialists collect the DNA by doing a simple and painless mouth swab from the inside of the cheek. All information is documented on a Chain of Custody, which ensures all test results are accredited and legally admissible.

Private DNA tests are treated the same as legal DNA tests in the laboratory, and they’re just as accurate. The difference is you can collect the DNA yourself in the comfort of your own home. You’ll receive your kit in the mail along with easy-to-follow instructions, collection envelopes, mouth swabs and a Chain of Custody form.  We also include a self-addressed envelope so you can send back your samples for testing.

If you have further questions, please view the Frequently Asked Questions page or contact a Certified DNA Specialist toll-free at 1-877-477-5661.