rucilla Roberts and Vanda Torous stared at the placental tissue of two babies—fraternal twins—and were stunned by what they saw. The twins had shared the same womb and obviously the same mother, who’d tested positive for SARS-CoV-2 during delivery, yet the babies’ individual placentas looked very different, Roberts recalls. The tissue of one of the placentas was severely inflamed, riddled with immune cells. The other one looked healthy. When Roberts and Torous, who are both pathologists at Massachusetts General Hospital in Boston, ordered tests of the placental tissue for markers of...…rucilla Roberts and Vanda Torous stared at the placental tissue of two babies—fraternal twins—and were stunned by what they saw. The twins had shared the same womb and obviously the same mother, who’d tested positive for SARS-CoV-2 during delivery, yet the babies’ individual placentas looked very different, Roberts recalls. The tissue of one of the placentas was severely inflamed, riddled with immune cells. The other one looked healthy. When Roberts and Torous, who are both pathologists at Massachusetts General Hospital in Boston, ordered tests of the placental tissue for markers of...WW…