Final answer:
The Supreme Court first upheld a gender discrimination claim in Reed v. Reed in 1971, which set a precedent for future gender discrimination cases and established the standard of intermediate scrutiny.
Step-by-step explanation:
The first case in which the Supreme Court upheld a claim of gender discrimination was Reed v. Reed in 1971. This landmark decision marked the Supreme Court's recognition of the Equal Protection Clause of the Fourteenth Amendment as applicable to gender discrimination, laying the groundwork for future gender discrimination cases.
Subsequent cases, such as Craig v. Boren (1976) and Clark v. Jeter (1988), solidified the use of intermediate scrutiny in cases of gender discrimination, requiring the government to show that different treatment is substantially related to an important governmental objective.
The criteria set by these cases continues to impact the legal standard applied in gender discrimination cases today.