On the second Sunday in May, American moms, grandmothers, godmothers and sometimes stepmothers are celebrated with cards, bouquets and breakfast in bed. According to the National Retail Association, the holiday has become one of the most profitable in America, with consumers expected to spend $33.5 billion. Celebrating maternal fertility has been a spring ritual across centuries, cultures and continents. Women have been prized for their capacity to bear children and secure survival of the species.