Kathleen Hartnett, the attorney for a transgender student athlete, was unable to define what a woman is when questioned by Justice Samuel Alito during Supreme Court oral arguments on Tuesday over state laws banning transgender in women's sports.

The issue of whether the justices should define sex, especially under Title IX, emerged as a key question during oral arguments.

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.

The Supreme Court on Tuesday appeared likely to uphold state laws that ban transgender athletes from participating in girls' and women's sports, wading for the first time into the contentious issue. The justices heard more than three hours of arguments in a pair of cases challenging laws from West Virginia and Idaho that require public school and collegiate sports teams to be designated based on biological sex at birth and restrict transgender girls and women from competing on teams that correspond with their gender identity.

Sen. Marsha Blackburn criticized Justice Ketanji Brown Jackson as the Supreme Court heard two transgender sports cases.

Becky Pepper-Jackson holds hands with her mother, Heather Jackson, outside the U.S. Supreme Court after arguments over state laws barring transgender girls and women from playing on female athletic teams on Jan. 13, 2026, in Washington.

It’s been a less than stellar year for trans activists. Shortly after taking office last January, President Trump signed

The Supreme Court is reviewing two cases from Idaho and West Virginia that will impact transgender athletes in women's sports.