I generally agree---like any other portrait, you try either to avoid the cliches or to subvert them from within.

This won't work for everyone, but I can't resist tooting my own horn about the one photo from my wife's pregnancy that I really like: http://www.flickr.com/photos/ntenny/...7605957020849/

I think there's a lot of potential in IR film for maternity shots and parent/baby portraits, but obviously it's something of a special effect to be used with care.