I was blown away by this video when I first saw it.  I know we've all seen images like this before in Biology class, but the beautiful way Alexander Tsiaras puts this together from the point of view of a mathematician is really something.  As you might expect, the video prompted a series of heated comments on both sides of the abortion debate. And I can certainly see where this type of video might lead to that.  But as the mom of two daughters, and a and scientist by training, I was simply awe struck by the beauty and precision of human development.  Let me know what you think!