I've been listening to old shows from CBC radio's science program, Quirks and Quarks. One of the topics was a very interesting discussion of the many variants between the usual male and female body types and why they are not so accurate. Here's a link to the Between XX and XY segment.

This is rather confused, but that's because I'm thoroughly confused and trying to understand what's going on.

Ask any young child what sound a train makes and the answer will be some variation of "Chug-chug-choo-choo". But think about that sound - it's the sound of a steam locomotive. I'm about to turn 60 and steam locomotives were retired before I became a teenager, yet that archetype still pervades society.