Twins Research Australia receives many queries from twins and their families interested in zygosity testing to determine whether a particular twin pair is identical (monozygotic or MZ) or non-identical (dizygotic or DZ).

Quite often, parents are misinformed during pregnancy and at birth regarding their children's zygosity - as prenatal scans displaying one or two placentas are not a reliable means of determining whether twins are identical or not (please read this research piece for more information).

If twins are the same sex and each have a placenta, or if there is doubt about the type of placenta, they could be identical - or non-identical twins. The best way to be certain is to do a zygosity test.

The two most popular methods of acquiring the DNA samples needed to determine zygosity (i.e. whether twins are identical or non-identical) are by collecting blood or cheek cell samples.

An Australian organisation, easyDNA, now provides the most competitive discounted zygosity testing rate available - which is exclusive to TRA members. It offers twin zygosity DNA testing with results in just 5-7 working days. Your test also includes a free express return envelope for your samples. The company has been operating in Australia since 2006 and has offices in Brisbane, Melbourne, Sydney and Perth. They can provide testing anywhere in Australia exclusively through their NATA and ISO 17025 accredited laboratory.

Their special discount of $79 off their usual rate of $199 is exclusive to all members of Twins Research Australia. This pricing is currently the most competitive available for zygosity testing. Please note that TRA membership is free; to learn more about how to join us please visit our join us page.

To request a zygosity test and obtain the special $120 rate, you simply need to:

1. Contact TRA on This email address is being protected from spambots. You need JavaScript enabled to view it. or free call 1800 037 021 to obtain the unique discount code.
2. Enter the easyDNA site*: www.easydna.com.au/twins-dna-test/
3. Click the Order Now link on the product page
4. Select the test order options as desired and click 'next' to order (we recommend stating that you are a TRA member in the comments' section on this page).
5. Complete all personal and order details. You will need to put the code provided to you by TRA in the 'discount voucher code' area. Please note that only valid ID's will receive the discount and will be verified by TRA.
6. Click 'proceed to payment' to then enter payment details and to complete your order. (Note; if an invalid code was entered, you will be alerted and taken back to the personal details page).

   * If ordering a kit by phone (1300 482 165) please inform the customer care agent that you are a TRA member and provide your TRA ID. Your discount will be applied once your ID has been verified by us.