"If we really want equality, why does that equality not extend to nieces who genuinely, truly love their uncles?" asked Bishop Hugh Gilbert of Aberdeen.
A planned discussion between the Catholic Church in Scotland and government officials have also been scrapped, as bishops believe the Scottish government has already decided to go ahead with the proposed legislation.
"The truth is that a government can pass any legislation it likes. Why is it all right for a man to marry another man, but not all right for him to marry two women?" Bishop Gilbert continued. "And, if you say that such things don't happen, that they are mere freaks of nature, extreme examples dreamed up for the sake of argument, I say you need to spend more time in the parish."
"As bishop of Aberdeen, I know there are gay people amongst the community of the Church. I promise I will always respect and love them and uphold them in their relationship with the God who loves them. But I won't marry them. It just can't be done," he added.
Pro-gay marriage group Equality Network, however, has called Bishop Gilbert's comments offensive and insists that his comparisons are without merit.
"We are very disappointed the Bishop of Aberdeen should choose to compare same-sex marriage to polygamy and incest. That is offensive and uncalled for," said Tim Hopkins, director of Equality Network.
The Church of Scotland has also official spoken out against the proposed legislation, calling the redefinition of marriage "detrimental."
"The Scottish government is embarking on a dangerous social experiment on a massive scale … We strongly suspect that time will show the Church to have been completely correct in explaining that same-sex sexual relationships are detrimental to any love expressed within profound friendships," the Catholic Church has said.