Nancy Mace rips trans athlete's attorney for refusing to define sex at SCOTUS women's sports hearing

ACLU attorney Joshua Block would not give his definition of "sex" after arguing on the floor of the U.S. Supreme Court that the definition should not be used when enforcing Title IX, then fled further questioning.

Rep. Nancy Mace, R-S.C., called out American Civil Liberties Union attorney Joshua Block for refusing to define sex after arguing against considering its definition during a Supreme Court hearing on trans athletes in women's sports. 

Block, who represents transgender athlete Becky Pepper-Jackson of West Virginia, urged the nine justices not to consider the definition of sex when ruling on Pepper-Jackson's case, and said, "I don't think the purpose of Title IX is to have an accurate definition of sex. 

Block later conceded, "I think for this case, you can accept for the sake of this case that we're talking about what they've termed to be biological sex."

The attorney then refused to give his definition of sex after the hearing when asked by Fox News Digital, and fled further questioning.

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Joshua Block, senior counsel with the ACLU's LGBTQ & HIV Projects and lead attorney representing Becky Pepper-Jackson, outside the US Supreme Court in Washington, D.C., US, on Tuesday, Jan. 13, 2026. (Kent Nishimura/Bloomberg via Getty Images)

Mace re-shared footage of Block dodging the question on X, condemning the ACLU for refusing to define ‘sex.’

"If the ACLU can’t even define what sex is, they have no credibility lecturing anyone about sex discrimination, which is the whole basis of their argument," Mace wrote. 

John Bursch, of Alliance Defending Freedom, the law firm representing female athletes and the state of West Virginia, said Block's insistence on not defining