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Thank you for being part of Gemini

What's coming up next for Gemini? (more)

Instead of a written questionnaire, the next part of the Gemini study is going to be carried out as a telephone interview. The aim of this part of the study is to obtain a clearer picture of the environment that young children are growing up in. There will be questions about the general environment as well as questions specific to each twin.

We are really excited about this next part of the study, and will start contacting families soon.

We are in the process of collecting telephone numbers for the Gemini families. If you are unsure whether we have your number already then please fill in the form here and we will add it to our records.

Zygosity results (more)

Over the past 9 months families have been collecting their twins' DNA for the Gemini study. We have been delighted with the response rate; however this has delayed our estimated arrival date for the results. At present we are expecting results by August 2010. As soon as we receive results we will be contacting the Gemini families via post.

The DNA information from the twins was collected for 2 reasons:

1. Analysis of DNA will allow us to look at genetic aspects of appetite and growth.

2. To confirm that the very first questionnaire you filled in about your twins' likeness is a good way of telling whether twins are identical or non-identical. This will involve checking the DNA of a small number of twins to make sure that the questionnaire and the DNA give the same answer.

If you haven't sent back your twins' DNA tubes yet, and would still like to, then it is not too late. However, please expect a delay in receiving your results.

Just to reiterate what was said in the information pack, we will be zygosity testing a random selection of the same-sex twins using DNA testing. This information will allow us to establish the accuracy of the questionnaire results in identifying identical and non-identical twins. The majority of participants will then receive the results of the questionnaire (which have been shown previously to be over 96% accurate). We are not able to zygosity test the DNA of every same-sex twin pair in the Gemini study because this would be extremely expensive and we are a charity funded study. We are also confident in the accuracy of the questionnaires and believe that they will accurately classify twins as either identical or non-identical in most cases.

We have had enquiries from families who are keen to have their children's zygosity tested through DNA analysis. In these cases we can offer those families (who are not in the randomly selected sample) an opportunity to pay £20 for this service. This is a greatly reduced price compared to private DNA analysis. If you would be interested in this option please let us know via email at

Growth reminder (more)

We recently sent out growth reminders to all Gemini families. We are aiming to send out reminders every 3 months which will help you to remember to weigh and measure your twins using the Gemini growth chart and scales.

You can send us measurements by completing our online form (click here) or by emailing or posting them to us at our freepost address.

If your scales are faulty or you need a new growth chart then please phone or email us at

Keep measuring!

Photos and stories (more)

We have been receiving some fantastic photos from the Gemini families. Have a look for them in our Gemini Gallery 2010. Do you have a photo or story you would like to share with the Gemini team and other Gemini families? If so, please email us at and fill in the consent form here.

What can DNA tell you? (more)

We are in the process of collecting DNA samples from all the Gemini children so that we can look for specific genes that influence appetite and growth. It will also help us to identify if the twins taking part in our study are genetically identical or fraternal (non-identical). To learn more about about why we are collecting DNA and how we will use it, read our information leaflet (click here). Read our story to discover why it is not always easy to tell if twins started out as one egg or two (Click here).

Weighing and measuring your twins just got easier! (more)

We are very excited to have been able to provide each Gemini family with their own electronic weighing scales and growth chart. If you have started to measure your twins' height and weight click here to send us your most recent measurements.

Information about Diet Diaries (more)

We all know the old saying "you are what you eat" well in the Gemini study we want to find out more about how what children eat affects how they grow. There are lots of ways of finding out what children eat but by far the most useful is by asking parents to keep a diary of exactly what their children eat over a few days. So the next task for Gemini families will be to complete a diet diary for their twins.

We know how busy it gets raising twins, let alone finding time to record their diet as well, so we have been working with some really helpful mothers of twins to design the Gemini diet diaries. The diaries are now easy and simple for Gemini parents to complete. We have combined space to record what both twins eat into one diary. If both of your twins eat the same food there is no need to write it all out twice, simply write "as twin 1". We've put lots of instructions to make it clear what information we need and we've added tabs so that the space for recording each day is quick and easy to find. We hope this will make the process of telling us what your children eat straightforward yet still provide us with really detailed and valuable information.

Where do Gemini families live? (more)

Gemini is a national study of twins with families helping us from all over England and Wales. Having families spread across Britain helps us get a clearer picture of what it is like for twins growing up including how things vary from the South to the North. We've mapped where our Gemini families are, click here to see how many Gemini families live in your area.

We have hit our target of 2400 families! (more)

The Gemini study is off to a flying start after successfully recruiting 2400 families with twins born last year. In partnership with the Office for National Statistics we asked everyone in the UK that had twins born between March and December 2007, nearly 6500 families, to help us out. Thanks to all of the families that have responded to our first questionnaire we have hit our target, which means we will be able to answer important questions about how genes and the environment work together to influence how children eat and grow.