"Is it not necessary for there to be, for equal protection purposes, if that is challenged under the Equal Protection Clause, an understanding of what it means to be a boy or a girl, or a man or a woman?" Justice Alito asked.

"Yes, your honor," Kathleen Hartnett, the lawyer from the ACLU, replied.

"And what is that definition, for equal protection purposes, what does it mean to be a boy or a girl, or a man or a woman?" Alito asked.

"Sorry, I misunderstood your question," Hartnett said. "I think that the underlying enactment, whatever it was, the policy, the law... We'd have to have an understanding of how the state or the government was understanding that term to figure out whether someone was excluded. We do not have a definition for the Court."

"Well, how can a court determine whether there is discrimination on the basis of sex without knowing what sex means, for equal protection purposes?" Alito asked.