Mary Cheney on Friday criticized her sister's assertions on gay marriage.

In a Facebook post, Mary Cheney, the openly gay daughter of former vice president Dick Cheney, said that Liz Cheney was “dead wrong” on the issue.

Liz Cheney announced last month that she will be challenging Wyoming Senator Mike Enzi in the Republican primary. Dick Cheney has previously said that he supports Mary Cheney's marriage to Heather Poe. Last year, the couple married in the District of Columbia, which legalized gay nuptials in 2009.

“I am strongly pro-life and I am not pro-gay marriage,” Liz Cheney said in a statement posted on her website. “I believe the issue of marriage must be decided by the states, and by the people in the states, not by judges and not even by legislators, but by the people themselves.”

“For the record, I love my sister, but she is dead wrong on the issue of marriage,” Mary Cheney wrote in response. “Freedom means freedom for everyone. That means that all families – regardless of how they look or how they are made – all families are entitled to the same rights, privileges and protections as every other.”

“It's not something to be decided by a show of hands,” she added, urging readers to share her post. “Please like and share if you agree.”

(Related: NOM's Brian Brown questions Liz Cheney's claim she's not “pro-gay marriage.”)