Do pregnant mothers have fetuses as parts? According to the “parthood view” they do, while according to the “containment view” they don’t. This paper raises a novel puzzle about pregnancy: if mothers have their fetuses as parts, then wherever there is a pregnant mother, there is also a smaller thinking being that has every part of the mother except for those that overlap with the fetus. This problem resembles a familiar overpopulation puzzle from the personal identity literature, known as the (...) “Thinking Parts Problem”, but it’s not merely a special case of that problem. Rather, the fact that late-term fetuses have a mental life of their own makes the Problem of Pregnant Thinkers, as I will call it, a sui generis and especially recalcitrant problem. (shrink)