Genetic issues FAQs

FAQs about genetic issues and conception

I am 36 and worried about my chance of having a baby with Down's syndrome.

The risk of having a child with Down's syndrome increases with age. Talk through the statistics and risks with your doctor and your partner. Tests can be carried out during pregnancy to gain a more accurate idea of your risk and to detect which babies have chromosomal disorders. While some couples decide not to continue with such pregnancies, others do and go on to enjoy their children.

There is a history of mental illness in my family. Will I pass this on?

It is important that you start by going to your doctor and talking through your concerns. Not all types of mental illness are hereditary and, while this has been a taboo subject a few years ago, both attitudes and treatment are changing.

I am heavily overweight and have dieted all my life. Will I be at risk of having children who are overweight?

While there may be some genetic link to obesity, the food that you eat and your activity level play a much more important role. Put simply, your activity level must balance with the calories that you are taking in.

Begin by seeking advice and support about your own diet and attitudes towards food. Make an appointment with your family doctor, practice nurse or before pregnancy consider joining a reputable slimming club. This will help you to make sure that you pass on to your children, good eating habits and attitudes towards food. See our Ready to conceive page for more information.

My mother is a non-identical twin. Am I more likely to have twins?

Identical twins are created when a fertilised egg divides into two and this does not usually run in families. Non-identical twins are the result of two eggs being released and being separately fertilised. Non-identical twins can run in families following the maternal line.

There is a slightly higher chance that you may conceive twins because your mother is a twin. Overall, women have a 1 in 80 chance of naturally conceiving twins. Read more about multiple pregnancy here

Read our top tips for getting ready to conceive.


  1. Macdonald S, Magill-Cuerden J, Mayes’ midwifery, fourteenth edition, Edinburgh Bailliere Tindall Elsevier, 2012
  2. National Institute for Health and Care Excellence, Antenatal and postnatal mental health, clinical guideline 45, London NICE, 2007
  3. Falchi M et al, Low copy number of the salivary amylase gene predisposes to obesity, Nature Genetics 2014; 46(5): 492–97
  4. National Institute for Health and Care Excellence, Weight management before, during and after pregnancy, London NICE, 2010
  5. Human Fertilisation and Embryology Authority, Sex selection, London HFEA, 2009. Also available at: (accessed 19 May 2014)
  6. Human Fertilisation and Embryology Authority, Multiple births and single embryo transfer review, London HFEA, 2013. Also availabe at: (accessed 19 May 2014)


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Last reviewed on April 1st, 2014. Next review date April 1st, 2017.

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