Whereas "marriage defenders" like Chuck Cooper seek to inform society that procreation is the "central purpose" of marriage for all people, in the above-referenced article we learn that it is actually quite rude both to assume and then to ask when newlyweds are going to have a baby. Disregard the annoying heterocentrism in this article, and watch MSN inform us that after marriage:
"Next comes whatever the bride and groom want, which may be buying a home, working toward a big promotion, or something else entirely. Everyone's got their own schedule and life goals, which may or may not include the pitter-patter of little feet."
So there you have it.
Marriage is not defined by the desire or ability for a couple to procreate. The institution means different things to different people. MSN said so. Which is at least more proof than, as Ted Olson quipped of Cooper's big Prop 8 procreation argument, "We don't have to prove anything. We don't have any evidence."