Story highlights Jeff Sessions' confirmation hearing is set to begin at 9:30 a.m. ET Tuesday

Lambda Legal has said Monday that Sessions "has demeaned and dismissed LGBT people"

Washington (CNN) The mother of Matthew Shepard is urging senators to oppose Alabama Sen. Jeff Sessions' nomination to become President-elect Donald Trump's attorney general, citing his opposition to hate crimes legislation.

In a report issued by the Human Rights Campaign, Judy Shepard -- whose son Matthew was beaten and left to die in Wyoming in 1998 in a crime motivated by anti-gay sentiment -- blasted Sessions for opposing the Hate Crimes Prevention Act, which President Barack Obama signed into law in 2009.

A Sessions spokeswoman, meanwhile, says he would enforce hate crimes laws as attorney general -- even though he opposed them in the Senate over constitutional concerns.

Judy Shepard's comments come just before Sessions' confirmation hearing, set to begin at 9:30 a.m. ET Tuesday before the Senate Judiciary Committee.

Judy Shepard wrote that Democrats and Republicans had helped push for hate crimes legislation in Congress, but that "Senator Jeff Sessions was not one of these members."

Read More