Milk kinship hypothesis in light of epigenetic knowledge

BACKGROUND: A wet nurse can be used if a baby’s natural mother is unable or chooses not to breastfeed her infant. The practice of using wet nurses is ancient and common to many cultures. PRESENTATION OF THE HYPOTHESIS: We hypothesize that infants breastfeeding from the same woman may develop consanguinity even in cases in which they are not blood relatives, and that children of two individuals breastfed by the same woman may thus be at risk of several genetic diseases because of such consanguinity. TESTING THE HYPOTHESIS: Possible evidence for the milk kinship hypothesis is to be found in the composition of breast milk, which is composed of living substances such as stem cells or substances that can affect epigenetic regulation such as microRNAs. IMPLICATIONS OF THE HYPOTHESIS: If these epigenetic modifications are heritable, marriages between individuals breastfed by the same woman may result in the same consequences as consanguineous marriages. In this paper, we attempt to assess this possibility.