Angus Walker explains why Vunipola has found himself facing criticism
Billy Vunipola has refused to unlike an Instagram post published by Israel Folau in which the Australia full-back made homophobic remarks.
The England international, the son of a Methodist Minister, says people should follow God's teachings more closely.
Folau said on Wednesday that "hell awaits" homosexuals in comments that have resulted in Rugby Australia stating they intend to terminate his contract, effectively ruling him out of this autumn's World Cup.
In an apparent show of support to his fellow Christian, Vunipola states that "Man was made for woman to pro create that was the goal no?"
However, England's first choice number eight adds that "I don't HATE anyone".
Vunipola will meet with the Rugby Football Union to discuss his response to the anti-gay position outlined in his post.
“Rugby is an inclusive sport, and we do not support these views. We will be meeting with Billy to discuss his social media posts,” the RFU said in statement.
The back-rower's club, Saracens, say the will deal with Vunipola internally.
“Saracens proudly embraces diversity and warmly welcomes everyone to the club regardless of race, gender, religion and sexual orientation," a club statement read.
“Our sport is open to all and we strive for it to be free from all forms of discrimination. We recognise that people have different belief systems and we expect everyone to be treated equally with respect and humility.
“As representatives and role models Saracens players have a responsibility not only to themselves but to the club and wider society. Billy Vunipola’s recent social media posts are inconsistent with this and we take this matter very seriously. It will be handled internally.”
Vunipola posted on Friday that he would not back down and unlike the Folau's image.
"So this morning I got 3 phone calls from people telling me to 'unlike' the @izzyfolau post. This is my position on it. I don't HATE anyone neither do I think I'm perfect," the Saracens back row said.
"There just comes a point when you insult what I grew up believing in that you just say enough is enough, what he's saying isn't that he doesn't like or love those people.
"He's saying how we live our lives needs to be closer to how God intended them to be. Man was made for woman to pro create that was the goal no? I'm not perfect I'm at least everything on that list at least at one point in my life. It hurts to know that.
"But that's why I believe there's a God. To guide and protect us and forgive us our trespasses as we forgive those who trespass against us."
Vunipola's mother is Reverend Iesinga Vunipola, a Methodist Minister, and the 26-year-old has repeatedly spoken of the strength he draws from his faith.
His recent career has been interrupted by a series of significant injuries, most notably three successive broken arms, but he appeared throughout England's recent Six Nations campaign.
Although he has yet to regain top form in the wake of his repeated spells in the treatment room, he will enter the World Cup as undisputed first choice in his position.