Higher Primates & Certain Bats This might seem rather disrespectful. In fact, it's sibling rivalry at its evolutionary best. You see, mother and fetus have quite distinct evolutionary interests. The mother 'wants' to dedicate approximately equal resources to all her surviving children, including possible future children, and none to those who will die. The fetus 'wants' to survive, and take as much as it can get. Found in Susan Sadedin’s answer to the question, “What is the evolutionary benefit or purpose of having periods?”
-Published in Persephone’s Daughters, Issue 3.