Why babies?

A curious question.  Several of the best movies over the last two years have featured infants.  Babies.  Not just children, but the real deal–snotty, wailing babies.  And in every movie they are essential to the plot and thematic sensibilities.  Usually the infant represents hope for the future.  I am reminded of David Patterson’s idea in When Learned Men Murder, that seeing and knowing a child’s face may prevent evil or unlock compassion.

Here are the movies I’ve recognized this recent pattern in:

Children of Men, Eastern Promises, L’Enfant, Juno, Knocked Up, Pan’s Labyrinth, Tsotsi.

Are there any others?  Is this pattern really recent, or have I missed a longstanding tradition?  And why (or why not) does it exist?

P.S.  I heartily recommend all the listed movies, except: Tsotsi and Eastern Promises are rather uneven and only half-good.  And Knocked Up is rather depressing.