From the oral arguments of Hollingsworth v. Perry, the landmark case to decide the constitutionality of California's Proposition 8, which made gay marriage illegal within California, an exchange between Charles Cooper, representing proponents of the law, and Supreme Court Justice Elena Kagan:
KAGAN: Well, suppose a State said, "Because we think that the focus of marriage really should be on procreation, we're not going to give marriage licenses any more to any couple where both people are over the age of 55." Would that be constitutional?
COOPER: No, Your Honor. It would not be constitutional.
KAGAN: Because that's the same State interest, I would think. You know? If you're over the age of 55, you don't help us serve the government's interest in protecting procreation through marriage. So why is that different?
COOPER: You, you, Your Honor, even with respect to couples over the age of 55, it is very rare that both couples — both parties to the couple — are infertile.
(Laughter from the gallery.)
KAGAN (interjecting): No really, because the couple — I can just assure you if both the woman and the man are over the age of 55, there are not a lot of children coming out of that marriage.
(h/t: Blogging via Typewriter, which has been following the oral arguments throughout the day.)