Once upon a time, brides came with free gifts called dowries. The idea was to make sure the groom had a little something to start with when he began running his own household -- things like money, tableware and new sheets. That was fine if you were rich, but it was awful if you were poor. How could you attract a husband when all you had to offer was love and a set of wooden bowls? What if marriage to the girl down the street came with silverware and a milking goat? How could you compete with a free goat?
Bridal showers to the rescue! These showers were originally parties where friends and relatives could "shower" a bride with all the equipment she'd need for setting up a house.
As dowries faded in popularity (good riddance!), the bridal shower stayed, making sure that new generations of brides were supplied with the gravy boats and steak knife sets that everyone needs but no one thinks to buy on their own. The shower is a practical tradition that's recently experiencing a new twist -- the couple's shower.
Rather than exclusive girls-only events, society is beginning to let the groom in on the fun.