The Susan B. Anthony List, a major anti-abortion rights group, is backing former Missouri Treasurer Sarah Steelman (R) over her two Republican opponents in the race to unseat Sen. Claire McCaskill (D-Mo.).

“Missouri women and families are hungry for a pro-life leader like Sarah Steelman,” said Marjorie Dannenfelser, the president of the group's PAC, adding that McCaskill "has failed miserably at representing the best interests of women.”

Both of Steelman's primary opponents, Rep. Todd Akin (R-Mo.) and businessman John Brunner, also oppose abortion rights.

A spokewsoman for the Susan B. Anthony List said Steelman's gender played a role in the endorsement, because the group has a special emphasis on female candidates.

McCaskill has been endorsed by EMILY's List, a PAC that assists Democratic female candidates who favor abortion rights.

- This post was updated at 5:18 p.m.