Why do humans tend to live such a long time? Our closest relatives, the chimpanzees, can last into their mid-forties in the wild. Yet somewhere in the last six million years, human lifespans have lengthened dramatically, so that living into our seventies is no big surprise.
Many expectant parents often joke about having a gender preference for their as yet unborn child: a boy, perhaps, to go to baseball games with dad, or a girl, to one day see her in a wedding dress. But what if those preferences could become a choice?
We're not the only girls in the animal kingdom who fall for the wrong guys, strategize about finding 'Mr. Right' and occasionally fend off the advances of unwelcome suitors. Like many other ladies, from beetles to chickens to dolphins, we're generally the 'choosy' sex.
You've probably heard the rumors that dolphins are the only other mammals that have sexual intercourse for pleasure. It appears as though this is almost true, depending again on how one defines sex for pleasure.