How do you know if you are identical or not?

The Australian Twin Registry 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).

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. Below are listed two organisations which provide such services.

1. Genetic Technologies Corporation Pty Ltd

Cheek Cell Sample - Mouth Swab Method. Cost = $165. PO Box 115, Fitzroy, Victoria, 3065. Phone number: Melbourne (03) 9415 7688; Sydney (02) 9906 3626; Perth (08) 9284 9662. Email: gtc@genetictechnologies.com.au

2. Victorian Institute of Forensic Medicine.

Blood sample - Fingerprick method. Cost = $330. Phone number (03) 9684 4337. Contact person: Natasha Redman, Scientist, Molecular Biology, Victorian Institute of Forensic Medicine, Department of Forensic Medicine, Monash University, 57-83 Kavanagh St, Southbank Vic 3006. Email Forensic@vifp.monash.edu.au

3. DNA Labs SydneyIVF

Cheek cell sample - mouth swab method. Cost = $280. GPO Box 4384, Sydney, NSW, 2000. Phone number (02) 9229 6495 or 1300 663 244. Email: dnalabs@sydneyivf.com