The decision, in a 20 to 10 vote by the society's governors, came after a divisive and emotional hearing Friday over Trinity Western University's controversial policy against sex outside marriage between a man and a woman.
The mail-in referendum is to be held as soon as possible, with results to be released at the end of October.
The hearing followed months of debate on the issue that three other provincial legal governing bodies have weighed in on, with the matter expected to eventually land in the Supreme Court of Canada.
Law societies in Ontario and Nova Scotia have voted against accrediting law students from Trinity, and the university has launched legal challenges of those decisions.
Earlier this month, members of the Law Society of New Brunswick passed a resolution directing its council not to accredit the law school.
In April, governors, also called benchers, in B.C. decided to accredit the new law school in Langley, south of Vancouver.
That triggered a non-binding vote in June by B.C. lawyers who voted 3,210 to 968 in favour of a motion calling on the society's governing body to reject accreditation of the school slated to open in the fall of 2016.
On Friday, governors who favoured the referendum said it would be the most democratic and transparent way for lawyers to express their views because most of the society's 11,000 members were unable to vote in person in June.
However, others, including Lynal Doerksen, who voted in favour of the law school in April, said the referendum will ultimately not be binding because only the courts can decide such a hot-button issue that has resulted in discrimination against minority Christian rights.
"In respect to Trinity Western, I feel that they cannot possibly win in the court of public opinion and that they will be on a level playing field in the courts," he said as one of the many impassioned speakers at the hearing.
Doerksen said he is in favour of the referendum because it may provide "an ironic result."
"The more successful it is the more it may show that Trinity Western is in need of protection from us."
While lawyer Maria Morellato agreed that the final decision must come from the courts, she voted against the referendum, saying the issue involves balancing the competing rights of two minority groups — gay and lesbian students and those who want to freely practise their religion.
"The most sensible and pragmatic approach is not, in my view, to have yet another vote but rather to diffuse the divisiveness about how we balance these rights, to honour each others' views to disagree without being disagreeable and to allow the courts to do their good and necessary work," she said.
"Ultimately, this issue will be decided by the Supreme Court of British Columbia and probably by the Supreme Court of Canada but once the Supreme Court of British Columbia issues its decision it will be the law and we're honour-bound by it and it will provide guidance."
But bencher Joe Arvay was vehemently against the referendum, saying that if the society disagrees with the "abhorrent" position of the university, then it should make its position clear now.
"For one thing, we will be very poor advocates if we go to the Supreme Court of Canada and argue against TWU having found in favour of them here."
Trinity Western spokesman Guy Saffold said the university is disappointed with the referendum decision after benchers had already approved the law school based on constitutional principles.
"We're still hoping that we'll be able to go ahead with the opening of our law school in the fall of 2016," he said, adding the curriculum has already been planned and approved and a director has been hired.
In 2001, the Supreme Court of Canada ruled in favour of Trinity over its teachers' college and the same so-called community covenant that students are required to sign, saying they will not have sex outside heterosexual marriage.
"We feel it's possible to hold to a Christian view of marriage and to do that with respect," Saffold said. "We very sincerely affirm the inherent dignity and rights of LGBTQ people and we hope to be able to hold on to our right to practise our belief as we've had it for 2,000 years without reflecting negatively on anyone else."
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