Rep. Justin AmashJustin AmashTwo-year defense spending smooths the way to a ready military House Oversight a gavel no one wants Trump, GOP at new crossroads on deficit MORE's (R-Mich.) primary challenger is attacking him on abortion, accusing him of voting to "allow gender selection abortions to continue."

Businessman Brian Ellis (R), who's trying to get to the right of the libertarian favorite on social issues, slams Amash for a vote against a bill brought by House Republicans that would have made it a crime to perform an abortion solely based on gender. Amash was one of seven Republicans who voted against the bill.

"It's called gender-selection abortion: killing an unborn baby because it's not the sex the parent wanted. Every Michigan Republican voted to stop this disgraceful practice, except one — Justin Amash. Amash voted to allow gender selection abortions to continue," the ad says. "Right to Life called Amash's vote 'shameful' and 'pro-abortion.' They're right. Amash's vote was very wrong."

Amash's campaign fired back, calling it "despicable, disgusting, beyond the pale — and false."

It reveals a profound lack of character," said Amash spokesman Will Adams. "West Michigan expects more — even from desperate politicians like Brian Ellis. Justin Amash is 100 percent pro-life and opposes abortion. In Congress, he has voted more than a dozen times to restrict abortion and uphold babies' God-given and constitutionally protected right to life. The legislation at issue would not have made a single abortion illegal. Instead, it would have created a thought-crime, which conservatives oppose."

Amash appears to have a major edge in the race, despite being a target of the Chamber of Commerce. He's received support from the Club for Growth and Americans for Prosperity, and has given Ellis little room to run to his right.

Ellis is spending approximately $75,000 on the ad buy, his first of the campaign. The primary is in August.