This study expands existing scholarship on the relationship between parental educational similarity and children’s birth outcomes using rich administrative data from Chile covering births that occurred between 1990 and 2015. We assess the applicability of the homogamy-benefit hypothesis – whereby parental educational similarity (educational homogamy) is beneficial for children’s outcomes – by testing the relationship between parental educational homogamy and two measures of infant health, namely low birth weight (LBW) and preterm birth (PB). We show that parental educational homogamy is associated with a reduced probability of low birth weight and preterm birth – particularly at the high end of the educational distribution – and the observed association is only partly driven by selection into homogamous couples, as demonstrated by additional analyses using a subsample of matched siblings from same mothers but different fathers. We further show that couples where women outrank men in educational attainment (educational hypogamy) do not exhibit positive birth outcomes relative to their homogamous counterparts, yet couples where men outrank women (educational hypergamy) do, suggesting that the homogamy- benefit hypothesis does hold, at least with respect to hypogamy. A municipality-level analysis merging external information on female labor force and gender gap in earnings prior to children’s birth reveals that the association between hypogamy and children’s outcomes becomes increasingly negative as female labor force participation increases (what we label the “double burden” of hypogamy), while it varies little by the earnings gap ratio – consistent with the idea that stringent social norms on the role of women in society underlie the association. Insights from this study contribute to a better understanding of the inequality debate surrounding the intergenerational transmission of advantage and disadvantage – a topical issue in a country that has recently joined the rank of the world’s wealthiest nations yet maintains extreme levels of inequality.