Don't worry, we're in no way promoting baby cannibalism.  this all has to do with that feeling some women get when they see a newborn infants, which makes them say crazy things like: "You are so cute, lil' baby; look at those sausage arms! I just want to gobble them up!"

According to a new study, it all has to do with the scent of newborn babies. Apparently the scent triggers the reward circuit in women's brains, causing them to feel joy in the presence of little ones.

This odor taken from the pajamas of unfamiliar 2-day-old infants and presented to groups of 15 women. One group was comprised of women who had given birth 3 - 6 weeks prior to the experiment; the second was made up for women who'd never given birth.

Brain scans showed that while both groups perceived the baby aroma with the same intensity, the caudate nucleus (which is the brain's reward center) was found to be more active among new mothers.
The olfactory—thus non-verbal and non-visual—chemical signals for communication between mother and child are intense. What we have shown for the first time is that the odour of newborns, which is part of these signals, activates the neurological reward circuit in mothers. These circuits may especially be activated when you eat while being very hungry, but also in a craving addict receiving his drug. It is in fact the sating of desire.
Thankfully, the researchers hypothesize that this response has evolved to encourage mothers to feed and protect their kids and not to eat them. Although when you really think about it, it's pretty freaky to think of your mom fighting the urge to munch on your chubby baby folds.

via Christian Science Monitor