One of the largest evangelical college ministries in the U.S. has asked any staff members who support same-sex relationships to quit.

Critics say the move is a purge, while supporters laud it as an affirmation of true Christianity.

InterVarsity Christian Fellowship recently informed all staff about the policy after issuing a position paper that says sex should be reserved for marriage between a man and a woman.

The Wisconsin-based organization's leaders said employees are expected to "believe and behave" in accord with its stand on sexuality. If they don't, they must tell their supervisors and leave within two weeks.

The new policy prompted a swift backlash on social media.

InterVarsity is the latest conservative Christian group struggling to navigate a country in which gay marriage is legal and 51 percent of younger evangelicals believe homosexuality should be accepted.