Summary of two studies comparing the birth weight of offspring of unions between different human ethnic groups.

<p>The study of Nystrom et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061116#pone.0061116-Nystrom1" target="_blank">[40]</a> compared European and Asian populations in the US, whereas our study compared European and Indian populations in the UK. The two parents are denoted by ♂ and ♀ symbols, with large font indicating the European population and small font indicating the Asian or Indian population. Paternal restraint refers to the deficit in birth weight induced by an Asian/Indian father compared to a European father, when exposed to a European mother. Paternal promotion refers to the increment in birth weight induced by a European father compared to an Asian/Indian father, when exposed to an Asian/Indian mother.