Those wily women with eyes 'false in rolling', who change their moods and affections like chameleons." Sonnet 20, William Shakespeare
400 years ago when the brilliant Shakespeare first penned this keen observation, commenting on the ever-changing nature of a woman's spirit, the knowledge that a woman's emotions could fluctuate with her hormones was unknown. The first hormone would not be discovered for another 300 years, and shortly after - the components of the menstrual cycle would be elucidated. Given the rapid advancement of science in the twenty first century and the ease with which peering into the brain has become; one would think the influence of the sex hormones estrogen and progesterone on cortical and subcortical regions implicated in a woman's emotional and cognitive processes would be fully understood. Not so.