Mitt Romney has defended the hiring of Richard Grenell, an openly gay man who resigned from his post earlier this week.

In his first remarks on the controversy, Romney told Fox News: “He's a very accomplished spokesperson. We select people not based upon their ethnicity or their sexual preference or their gender but upon their capability.”

Grenell's hiring sparked an outcry from some Christian conservatives who chided Romney for placing an openly gay man in such a high-profile position.

In a statement, Grenell said he felt his ability to do his job was “greatly diminished by the hyper-partisan discussion of personal issues.”

Romney did not address those who criticized the hiring of Grenell.

According to media reports, the firestorm of protest from conservatives prompted the campaign to advise Grenell, hired as a foreign policy spokesman for the campaign, to keep a low profile during an April 26 conference call he had organized to denounce President Barack Obama on national security.

An unnamed Republican adviser told The New York Times that the campaign was not concerned about Grenell's sexual orientation but “didn't want to confront the religious right.”

(Related: Jon Stewart mocks Bryan Fischer's hostility to Mitt Romney's gay hire Ric Grenell.)