Finally, a convincing account of the enigmatic Hofbauer cell, a type of macrophage that is the only immune cell of fetal origin found in human placenta. It is confirmed that it is derived from the erythromyeloid lineage expressed in the yolk sac and placenta. Although here characterized as "primitive erythropoiesis" it is worth noting that the erythromyeloid lineage continues into adulthood in mice and is the source of tissue-resident macrophages in liver (Kupffer cells) CNS (microglia) and skin (Langerhans cells) {1}. Importantly, the present paper presents evidence for an antimicrobial action of Hofbauer cells. Additionally, it was shown that placenta contains a related cell type of maternal origin here named placenta-associated maternal monocyte-derived macrophages (PAMM). Previous studies may have failed to distinguish between this cell population and true Hofbauer cells. These macrophages are found at breaks in the syncytiotrophoblast and are suggested to play a role in tissue repair. PAMMs were identified as early as seven weeks gestation in line with recent evidence of limited circulation in the intervillous space at this time {2}. On a historical note, Hofbauer cells were once referred to as Chaletzky cells since first described from hydatidiform moles by Eva Chaletzky (1870-1947) an early representative of women in STEM who was an activist for equal rights for women doctors in the Balkans (details in my paper {3}).