The Evangelical Alliance is a Christian organization representing a range of churches and individuals.
Mr Smyth also said: “I think we have to be careful not to create new secular blasphemies.”
“Is it secular blasphemy to believe that a man cannot biologically become a woman?” he continued.
Mr Smyth told the committee that while the Evangelical Alliance had some “concerns” about the content of RSE, it was not a case of “religion versus RSE”.
“We have no intention of waging a culture war where children are the victims,” Smyth said.
“There are so many similarities between Christians and non-Christians when it comes to teaching healthy relationships, consent, preventing violence against women and girls, and sexualization.”
But he said parents were concerned about some of what they had read in the media about what was being taught in RSE.