Brothers and sisters

We can learn a huge amount about the causes of health and well-being by comparing children from the same family. We also want to gather information so that we can study siblings in their own right. We now have some new funding to look at the health and wellbeing of the brothers and sisters of our original Children of the 90s.

If you are 16 or over and the brother or sister of a Child of the 90s, this is a great opportunity for you to take an active role in one of the world's most important long-term health research projects. We would very much like you to enrol in the project in your own right – not only biological brothers and sisters, but also half, step, foster and adopted brothers and sisters. 

Did you know?

  • Over half of the young people in the study have one sibling (brother or sister).
  • Almost a third have two siblings.
  • More than ten percent have three or more siblings.

How to enrol

To enrol as a Children of the 90s brother or sister, please print and complete the Siblings enrolment form (PDF, 48kB). You can complete this form even if you think you may already be enrolled.

Please send your completed forms to or Children of the 90s, Oakfield House, Oakfield Grove, Bristol BS8 2BN.

Further information for brothers and sisters

The study has been going on for many years – why do you want to enrol me now?

Children of the 90s began by studying pregnant women who lived in the Avon area between April 1991 and December 1992. A brother or sister of yours was one of them! Many of the mothers, fathers and children have spent the last 21 years helping us with our research.

Firstly, we would like to look at your health and welfare in relation to your brothers and sisters. We can learn a huge amount about the causes of health and wellbeing by comparing children from the same family. We also want to gather some information so we can study you in your own right. Many brothers and sisters have already said they want to be involved in their own right and now is your chance.

If I sign up, what happens then?

Filling in the registration form just gives us permission to contact you or send you mail directly. You will be asked separately about taking part in different areas of the study. All Children of the 90s activities are entirely voluntary. You can do as much or as little as you like. In the next few months we will ask you to fill in a questionnaire and provide us with a saliva (spit) sample, which contains your DNA.

I am not biologically related to either the study child or mother – are you still interested in me?

Yes we are! We are equally interested in both biological and non-biological (step) brothers and sisters as all family members have an influence on each other. Health and wellbeing are affected by many factors, both social and genetic. This means that a step-brother or sister is as important to us as a biological one.

We will not be checking whether you are biologically related to your other family members and will rely on you to tell us this. We will not tell your other family members anything that you have told us as all information you give us is confidential.

I am already a Child of the 90s – do you want me to sign up again?

Some of our study families have two or more children already enrolled as Children of the 90s – for example if your mum had twins or gave birth twice during 1991 – 1992. If you are already enrolled as a Child of the 90s in your own right this study doesn’t apply to you and you don’t need to send these forms back!

Will you want my DNA?

In short, yes! Your DNA will help us to study how genes affect behaviour and lifestyle, and how this affects the family environment. Your DNA will help us to look at your own health and also at genetic aspects of health within Children of the 90s families.

A child’s genes come from both mother and father, so its better if we are able to look at both parents and all their children. That’s why studies looking at conditions such as asthma, obesity or diabetes need to look at DNA from all family members.

How can I enrol?

We have posted a Brothers and Sisters Enrolment Form that we would like you to complete and send back to us. Siblings enrolment form (PDF, 48kB) if you do not have a paper copy. You must be 16 or over and we only require your signature on the form to enrol you in the study.

What are the possible disadvantages and risks of taking part?

The main disadvantage is giving up your time to fill in questionnaires and provide the saliva sample.

Nothing is compulsory and you are not committed to take part in any further activities even if you return the completed enrolment form.

What are the possible benefits of taking part?

There will not be any direct benefit to your health by taking part in our research. However you will be playing an important role in developing our understandings of health and disease. The findings from the research could one day benefit a future generation of your family.

How confidential will my information be?

The information we collect from you will be stored for use only by Children of the 90s and our research colleagues. The research data is labelled with a study number only, so it cannot be linked to you. Your personal details are stored separately and securely. This means you can be sure all your information will be held confidentially, including from the rest of your family.

Will anyone else know that I am taking part?

Any communication between you and the study would be confidential and we will not tell anyone else.

Who has approved this study?

The ALSPAC Executive Committee - this is a group of the senior researchers and managers who work in Children of the 90s.

The ALSPAC Ethics & Law Committee, made up of experts in research ethics and study participants, approved the study.

What happens if I enrol and then change my mind in the future?

You are free to withdraw any time. Just let us know and we will make the necessary changes. Your decision will not affect the participation of anyone else in the study.

What plans do you have for the future?

We hope to continue collecting information from you, through questionnaires and possibly even visits to our clinic in Bristol. We will also ask you if you are happy for us to access your official records, such as health and education records. At the moment, study mothers and fathers are being invited to take part in clinic visits. We are also planning another clinic for the original Children of the 90s when they are 24 or 25. If you would like to know more, explore our website or follow us on Facebook or Twitter.

I have more questions. Who can I ask?

Please contact our Participation Team by phoning 0117 331 0010, texting ‘SIB’ and your name to 07789 753 722 or by emailing


Children of the 90s has become a world-leader in genetic research, analysing the genome – or genetic blueprint – of thousands of participants

BBC News

Taking part in Children of the 90s

Edit this page