Depends how you phrase the question? If the question was should gay union be called the same as man and wife union i.e. marriage than much less than 50% I suspect . However if phrased " as should gays have right to marry "than 50%. Clever pollsters swing the polls to desired results. My attitude is perverts (defined by Oxford dictionary as leading away from what is natural) should have the right to full legal union but should be imaginative enough to derive their own term for this union and leave the universally accepted term marriage for normal husband -wife unions.
