Labour MP Ben Bradshaw today told the House of Commons that "serious questions" will be asked about the Church of England's established status if it stands by its position on opposite-sex civil partnerships.
A statement by the College of Bishops last month said that sex was for married heterosexual couples only.
"For Christians, marriage – that is the lifelong union between a man and a woman, contracted with the making of vows – remains the proper context for sexual activity," the document said, adding that "sexual relationships outside heterosexual marriage are regarded as falling short of God's purposes for human beings".
While many evangelicals welcomed the statement, it was met with a strong backlash by liberals in the Church of England. Some argued that it undermined the Church of England's Living in Love and Faith review process examining issues of sexuality, the findings of which are due to be published later this year.
The Archbishops of Canterbury and York quickly issued an apology for the "hurt and division" caused, saying that the document had "jeopardised trust", but they stopped short of withdrawing it.
In the Commons on Thursday, Mr Bradshaw grilled Andrew Selous, the Second Church Estates Commissioner, on the guidance.
"It is bad enough that the Church still treats its LGBT+ members as second-class Christians, but to say to the child of a heterosexual couple in a civil partnership that they should not exist because their parents should not have had or be having sex is so hurtful," he said.
"Will he tell the bishops that unless this nonsense stops serious questions will be asked in this place about the legitimacy of the established status of the Church of England?"
Responding, Mr Selous said he would "certainly feed back" Mr Bradshaw's "strongly felt concern" to the College of Bishops.
"In their apology, the Archbishops did recognise that the pastoral statement had jeopardised the trust that has been built up as part of the Living in Love and Faith project, which is intended to discern the way forward for the Church of England on this issue," Mr Selous said.