It's noteworthy that when the case for gay marriage first came before the Commons – with the then-Liberal government hotly denying that gay marriage would lead to polygamy – it was disclosed that a committee of its own Justice Department had already reached the conclusion that gay marriage would make polygamy inescapable.
What made the Ontario case possible, however, was modern technology and the process of in vitro fertilization. How much else might become inescapable is outlined in a book by professor Margaret Somerville of the McGill University Centre for Religion, Ethics and the Law, whose repeated warnings of the dangers to public health involved in the gay lifestyle saw her denounced by the liberal left. In her current "The Ethical Imagination: Journey of the Human Spirit" (Anansi Press, Toronto), she warns of other possibilities from human reproductive engineering, such as: - Creation of a chimera, a human-animal combination, possibly sought as an inherent human right by someone wanting to perpetuate himself or herself with a pet dog or cat.
Finally someone had the guts to say it -- if we allow same-sex marriages, before you know it there will be human/cat hybrids (I call them hucats) walking the streets.
This isn't the time or place to fully elaborate my objection to hucats, but suffice it to say those objections are religious, ethical and allergic.