"As a pro-life conservative, a husband and a father of two young women, I find Rep. Akin's remarks to be offensive and reprehensible," said Rehberg in a statement blasted out by his campaign late Sunday night. "There is no such thing as a 'legitimate rape.' I condemn Rep. Akin's statements in the strongest possible terms."

Akin told a St. Louis-area TV station this weekend that pregnancy from "legitimate rape" was rare because of biological reactions, as he sought to explain why he opposes abortion even in cases of rape.

"It seems to me, first of all, from what I understand from doctors, that's really rare. If it's a legitimate rape, the female body has ways to try to shut that whole thing down," he said.

The comment quickly triggered a national firestorm. A number of Republicans slammed him for the remarks, warning that they might have cost the party one of its best chances at picking up a Senate seat, and the Romney campaign released a statement disagreeing with his comments.

Akin later said he "misspoke" and that his remarks do not "reflect the deep empathy I hold for the thousands of women who are raped and abused every year." But he did not walk back his medical claims or belief in "the protection of all life."

The comments from Rehberg, an anti-abortion-rights conservative in a Republican-leaning state, show how dangerous Akin's comments could be for him and other Republicans. They also echo comments from Sen. Claire McCaskillClaire McCaskillOversight panel demands answers on Pentagon waste report Messer eyes challenging Donnelly for Indiana Senate seat Overnight Defense: Funding bill would ease Trump Defense pick's confirmation | Obama delivers final security speech MORE (D-Mo.), Akin's opponent, that she was "stunned" by the "offensive" remarks.

Rehberg has made a recent habit of bucking his party. He was one of only four House Republicans to vote against Rep. Paul RyanPaul RyanOvernight Healthcare: Burwell huddles with Dems on fighting ObamaCare repeal Reid: Bring back the earmarks Ryan: GOP won’t ‘pull the rug out’ from 'Dreamers' MORE's (R-Wis.) budget in 2010, and the Montana state party ran an ad this summer saying he "refused to toe the party line" on "Bush's Wall Street bailout" and "a Republican budget plan that could harm the Medicare program so many of Montana's seniors rely on." But this direct attack on another GOP Senate candidate is a step further than he'd previously gone.

The Hill rates both races "toss-ups."