Despite general attitudes suggesting teenagers are becoming more sexualised, eight out of ten churchgoers hold the belief.
New research published by Premier Youthwork Magazine also found a more liberal stance on homosexuality, with only 36% believing it to be a sin.
Writing in this month's edition Rachel Gardner, founder of the Romance Academy, expressed her suprise in the findings on sex. She said: "Let's not pass over how radical this is.
"We're hearing how peer-on-peer sexual violence is more widespread that we think and being a teen virgin denotes that something is profoundly wrong with you.
"So to say that you think sex is best understood and expressed in marriage, and then to try and live out the implications of this is to go against the tsunami of peer opinion and affirmation; it just doesn't easily happen, unless young people involved have a grabbed a greater vision than the one on offer."