National Geographic is offering a new DVD: The Biology of Prenatal Development. Dave Andrusko reviewed it yesterday in his "News and Views" column for NRLC, here.
The video, produced by The Endowment for Human Development, combines imagery of the unborn child within the womb using multiple imaging technologies with information from the medical literature. You can read Dave's review of it at the above link. It sounds like an excellent resource for introducing and studying prenatal development. I plan to order one for use in high school.