Marriage, as those who hope you will reproduce, demand that marriage is between a man and a woman. The purpose is to have the proper form of sex, with the consequence of said-act to make babies.
Marriage in a civilized society is the joining of the life experiences of two people in a socially and legally recognized Union. Joining of strengths to offset weaknesses. Man and woman. Man and man. Woman and woman.
When you are sterile...your view on traditional marriage makes you hope to...at least once...employ the Darth Vader "force choke" on fundies.