I just thought this was so fascinating. It makes me see what a crapshoot having a baby can be, and also how strange evolution can be. It's a little long, but worth it, I think. It also makes me terrified to have kids, or more accurately go through labor, because it seems like every strategy has it's outcomes, and I'd never seen them so outlined.
http://www.newyorker.com/archive/2006/10/09/061009fa_fact?currentPage=1