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Prof Melinda Mills: The Role of Genes in Fertility

On Wednesday, October 14th 2015 Population Europe held its second webinar of the year. It was the first to be hosted from Brussels, where the Population Europe Information Centre was opened in May.

The webinar, titled “The Role of Genes in Fertility,” featured Professor Melinda Mills (University of Oxford), whose cutting-edge, interdisciplinary research combines biogenetic and social scientific methods to shed new light on demographic issues that are, in Mills’ own words, themselves “very biological” processes.


Technically Speaking

In her presentation, Mills explained new data had allowed researchers to move beyond the candidate gene studies of the old days, which often resulted in false positives, to genome-wide association studies using techniques like GREML—genomic-related-matrix restricted maximum likelihood. The results in molecular genetics alone have been fascinating, but the new techniques also allow the field to be extended to demography. For instance, she reported that an evolutionary tendency toward lower age-at-first-birth (AFB) and higher number of children ever born (NEB) among women in Europe was in fact being overridden by social factors [2]. The result naturally raises questions about fertility, health, and the interaction of social and biological factors in demographic trends like involuntary infertility.


The Road to Biodemography

The webinar was not limited to methodology, however. Professor Mills’ presentation also contained a narrative, insight into how her sociological background led to a biodemographic approach and why it matters.

She pointed out prevailing explanations for variations in fertility had been sociology-dominant for many years. Such explanations point to values, gender roles, wages, education and working conditions, to name a few. Yet biological factors had already been applied to mortality, and with great effect.

“We’ve often had a biodemographic approach in relation to mortality, but there’s been less research in relation to fertility,” she said. “It’s very surprising we have ignored the biological and genetic basis of fertility.”

A lack of data, interdisciplinary training and academic interest had prevented advances in molecular genetics from contributing to fertility studies. All of these are now being overcome, she explained.


Ask Your Questions

A Q&A following the presentation allowed Mills to connect her research to larger academic and policy developments, as well as to the attendees themselves. As for policy, she suggested that only through a thorough discussion on the ethical use of findings in genetic studies by policymakers can the field move forward at pace, but felt that discussion was indeed taking shape. Going forward, she suggested there was some room to create policies more sensitive to “how late you can wait” to have a child—especially important in economies, like most in Europe, where women’s incomes rise as childbearing is postponed.


Sneak Peek

The invitation-only webinar was well attended, with around 30 researchers and policymakers tuning in. Attendees were not only able to interact with Professor Mills throughout the presentation and in the Q&A, but also given an inside look into her forthcoming publications: “Human Fertility, Molecular Genetics, and Natural Selection in Modern Societies” [1], and “A Behavioural Genetic Study of Age at First Birth of Female UK Twins” [2].

Both studies were carried out in conjunction with the Sociogenome Project. For an introduction the field, she invited attendees to read her and her colleagues’ review of the literature on Biodemography and fertility [3].

[1] Tropf, F. C., Mills, M., Barban, N., Stulp, G., and H. Snieder (2015) Human fertility, molecular genetics and natural selection in modern societies, PLOS ONE, DOI: 10.1371/journal.pone.0126821 [link]
[2] F. C. Tropf, N. Barban, H. Snieder, M. Mills, J.J. Mandemakers (forthcoming) “A Behavioural Genetic Study of Age at First Birth of Female UK Twins” Population Studies. [link]
[3] Mills, M. & F. Tropf (2015). The biodemography of fertility: A review and future research frontiers, Kölner Zeitschrift für Soziologie und Sozialpsychologie,  67(1): 397-424. [link]