Genetic variants linked to fertility identified

The number of children a person has may be influenced by their genome, according to an international study.

Led by researchers at the Universities of Cambridge, Oxford and Pennsylvania, the research identified genetic variants affecting both biological and behavioural factors that have an impact on whether a person is likely to have children, and how many.

'This study is the largest of its kind and has highlighted new biology that we anticipate will help identify novel therapeutic targets for reproductive diseases such as infertility,' said corresponding author Professor John Perry from the University of Cambridge. 'It will also help us better understand the biological mechanisms that link reproductive health to broader health outcomes in men and women.'

The research, published in Nature Human Behaviour used genomic data from over 785,000 people of European ancestry – including UK BioBank data – and compared this with the number of children born to each person.

This allowed them to identify 43 regions of the genome containing genetic variants associated with whether a person has children and how many. These effects appeared to be mediated through a diverse array of mechanisms, including the timing of puberty and menopause, hormone levels, risk of endometriosis and risk-taking behaviours. One gene variant was associated with having more children, but also with having a shorter reproductive lifespan.

Another gene identified was MC1R, associated with red hair, although the authors point out that its influence on the number of children people have appears to be separate from the genetic mechanisms involved in pigmentation.

The same team at the University of Oxford, led by Professor Melinda Mills, previously published work identifying genetic variants associated with reproductive behaviours such as age of becoming a parent (see BioNews 1103).

The authors acknowledged that their use of data from people of European ancestry only is 'problematic', and Professor Mills said: 'Future extensions of this work will examine diverse non-European populations.'