Not necessarily Dd. Some marsupials are born the size of small tadpoles, and migrate to a pouch outside the womb for further development. You can't make that generalization. The koala is 1/2 a gram (the size of a small insect) at birth. You're looking at gestation and birth bass-ackwards I think.
Marsupial's don't require "care" in the sense that the mother is nothing more than a giant feeding tube. Humans have to "care" for their young in the sense that they have to actively watch over another life form in order to ensure it's survival. Dd's point does seem a little over-generalizing, though.
I was always taught that human problems with birth are more directly linked to our upright posture rather than to our large brain size. The female hip system is actually this weird in-between stage that can't quite stand up perfectly and can't quite give birth perfectly, either. Plenty of other animals have large brain/hip ratios, but because of the way the hips are designed to bear weight they are allowed to be wider. It's part of the idea that humans are (more or less) an actively evolving lineage. The human race as we know it today is not some evolutionary perfection, but rather just another step in the species chain. Given another few hundred thousand years, a "more perfect" line of
Homo would have outcompeted and eliminated homo sapiens, much like we probably eliminated our sister species before us. Another example is wisdom teeth - most human lineages are actively evolving a smaller set of adult teeth (there was an evolutionary reason but it escapes me at the moment) by crowding out a tooth from each row. That's why they're such pains in the asses - our evolutionary line is in the process of getting rid of them.
Course the last course on humans I took was gen bio. *shrug*
EDIT: I also saw a few mentions of people trying to compare souls in humans with the souls in "lower life forms". Don't ever forget that from a biological sense primates are awfully low on the evolutionary totem-pole - rodents, insects, orchids, and grasses are far more derived and ecologically successful than you will ever be. My take on it is this: the "soul" is our feeble explanation at an incredibly complex biological system going on inside our heads. Kind of like how old chemists figured "ether" was a good explanation for basic chemical processes. Unfortunately, most of history's most brilliant minds have been busy studying black holes and inventing ED medicines and shit like that.
I like posting.
