Approved Research

Assortative mating in the UK Biobank: intergenerational health implications

Lay summary

This project explores genetic and phenotypic (i.e., non-genetic traits) similarities in human couples for a diverse range of genetic and phenotypic traits. Mating with similar individuals is described as assortative mating (AM), and there is considerable debate about the health consequences of this behaviour. Current empirical tests of this are contentious, so further research is required. This project tests whether AM is associated with fertility (i.e., number of children born) and offspring (viability (i.e., child health) in a novel population. It does this over multiple generations, testing not just whether offspring are affected by parental AM, but whether those offspring themselves go on to be affected. In doing so, it provides insights into whether AM could lead to the intergenerational transmission of health risk.

The scientific and health implications of this are considerable. The causes and consequences of AM have been the subject of intense academic interest and speculation for decades (Robinson et al. 2017; Abdellaoui et al. 2014; Bereczkei & Csanaky 1996; Thiessen & Greg 1980). If the behaviour is associated with high fitness (e.g., improved fertility), it might suggest an adaptive function (i.e., the it was selected for during human evolution). If the opposite is true, it will raise questions about how the behaviour has been maintained, potentially implicating sociocultural factors. Understanding the relationship between AM and offspring health could be important for medical researchers, but it is also of public-health interest. For example, it has been suggested that AM for body-mass-index has led to the intergenerational transmission of overweight, contributing to the "obesity crisis" in the developed world (Speakman et al., 2007). In terms of duration, the project is expected to last until 2022-23.

Current Scope:

1. What are the patterns of genetic and phenotypic assortative mating (AM) in the UK Biobank?
2. How do genome-wide and trait-specific AM affect fertility and offspring viability?

2.1. To what extent are associations explained in terms of sociocultural confounders?

New Scope:

1. What are the patterns of genetic and phenotypic assortative mating (AM) in the UK Biobank?

1.1. What are the health implications for mated pairs and how do these differ in same- and opposite-sex mating contexts?

2. How do genome-wide and trait-specific AM affect fertility and offspring viability?

2.1. To what extent are associations explained in terms of sociocultural confounders?

New Scope (update):

1. What proportion of couples inferred using the "gold-standard" household data method are genuine?

1.1. What is the false-positive rate for inferred couples across different subpopulations?