Another theory, she offers, “is that women tend to be caregivers.” Women, by definition, are there when the baby is born, whereas the man might’ve flown the coop. A caregiver might need higher protection from disease. Women generally have more body fat than men, so perhaps they have more immune system cells, Dr. Hahn postulated to me.
Biological evolution's really out here trying to keep the (female) nurturers alive. And all by *potentially* giving them more immune system cells! Cool beans.
