Why do women have MONTHLY periods?

phippsmartin_at_hotmail.com
Date: 03/21/05 

Date: 20 Mar 2005 16:30:15 -0800

Think about it. Women have periods every month. Why? Why not every
week or every two months? Ancient people would have associated the
woman's period with the phases of the moon. Is there any reason to
believe that the phases of the moon affect women's menstral cycles?

Martin