Twins and Higher Order Multiples (HOMs), including triplets, quadruplets and quintuplets of all ages, sex combinations and zygosity are eligible to enrol with Twins Research Australia. Twin pairs and HOMs are registered via completion of a registration form online by either the twins or by their parents if they are under the age of 18 years.

The numbers of new registrations by year, since 2004 are represented in the graph below.
TRA Twin registrations by year
Number of new twin and HOM sets registered with TRA by year since 2004.

*2012 peak: Merge of Western Australian Twin Registry with Twins Research Australia


A key avenue for TRA’s twin recruitment is through AMBA. There is a strong and long history of the two organisations working to support each other’s needs. Other avenues of recruitment are the offer of a free Twin Booklet to women who are pregnant with twins, Twins Plus Festivals and general media exposure on twin research findings.

The integration of the Western Australian Twin Registry (WATR), a population-based sample of twin pairs from 1974 onwards, has provided sustainability, prevented duplication of recruitment, and combines expertise. WATR identifies twins via state birth records, making this cohort an important sample epidemiologically (Hopper et al., 2006; Lee & Palmer, 2006). The increase in twin recruitment in 2011 and 2012 reflects integration with the WATR and TRA’s raised profile in the media. 

Participation in Research

Once twins join TRA they are invited to participate in appropriate and approved studies. Invitations are extended to twins depending on the requirements of the study, and the profile and the interest areas of the twin members.

The experience with TRA and associated studies is critical to maximising participation in studies. To this end, TRA maintains a quality assurance program that incorporates surveys of random samples of participants in all studies to ascertain the participant’s perspectives. The collected information is analysed and used to inform continual improvements and modifications, and to ensure member expectations are being satisfied.

Twins Research Australia

Address: 3/207 Bouverie St
Carlton, Vic 3010


ABN: 84 002 705 224

Twins Research Australia has received continuous funding from the National Health and Medical Research Council (NHMRC) since 1981, most recently through a Centre of Research Excellence Grant (2015-2022). TRA is administered by the University of Melbourne.

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