The Christian Institute has written to rugby’s national governing body calling into question its impartiality.
It follows England player James Haskell saying taking an orthodox view of the Bible is a ‘road map to killing people’.
So far he has received no sanction from the Rugby Football Union (RFU), but another English player – Billy Vunipola – has been disciplined for expressing Christian views.
The letter follows a row over an Instagram post from Australian international Israel Folau, which resulted in him being sacked.
Vunipola ‘liked’ the social media message and also posted about his Christian view that sex should be reserved for opposite sex marriage.
Writing to the Head of Discipline at the RFU, Institute Director Colin Hart said: “Vunipola believes himself to have fallen short of God’s standards. He holds to mainstream Christian teaching that “all have sinned and fall short of the glory of God” (Romans 3:23).
“He holds to the Easter message of hope that sins can be forgiven through trusting in Christ’s death on the cross and his resurrection from the dead.”
Mr Hart added: “The belief that sex is only for marriage is a belief worthy of respect in a democratic society” which was “recently re-affirmed by the Supreme Court in Ashers bakery case”.
He asked if the RFU could “confirm that it is willing to engage players who agree with this view about marriage”.
While Mr Hart acknowledged the proper place for social media rules, he said they “must be clear and reasonable, and they must be applied consistently and without discrimination”.
Mr Hart then drew attention to Northampton’s James Haskell who “responded to the Israel Folau post with vituperative, foul-mouthed abuse aimed at Folau personally”.
The Christian Institute’s Director said Haskell, “then followed up calling the texts of all religions ‘out dated’, asserting that Folau’s interpretation is a road map to killing and singling out ‘some team mates’ for scorn. Hardly moderate. Does the RFU propose to take no action against Haskell?”
At the time of writing, the RFU had not responded to the Institute’s letter.