Birth and sex are often talked about as if they were contrasting experiences. In fact, they each involve the same rush of hormones in an action drama in which mind and body work in harmony. When a woman is free to follow her instincts and give birth naturally, waves of endorphins surge in the bloodstream with the same energy as in ecstatic lovemaking. Birth and sex mingle to become one in the thrilling, sweet, intense and overwhelming experience of...