If We Legalize Gay Marriage, What About Incest, Bestiality, Pedophilia, etc.? 3

Lance probably came the closest to explaining the merits and pitfalls (as I see them) of this argument (i.e. equating homosexual marriage with incest, etc); however, I'll clarify. In short, it's actually the gay rights advocates that make this direct comparison (or at least subject themselves to this argument) by using the "being gay is genetic so society must accept it" line of reasoning. This of course begs the question of what happens if pedophilia is genetic or bestiality is genetic. As abundantly evidenced by most of the prior comments, this counter argument is met with a "but..." (e.g. consenting adults, no harm to society, etc). The problem with this is that it's the "buts" that are the crux of the issue. Gay marriage opponents do not concede that consent is determinative, and they certainly don't agree that there is no harm to society. Moreover, adults can certainly consent to incest and polygamy. This simply leaves the opposing sides back at square one. The slippery slope aspect of the argument is one of those that may be fun at parties but is best left to constitutional rights (which doesn't really apply here notwithstanding claims to the contrary). Bright line laws are used to keep from such slopes (think First Amendment), but for the vast majority of matters (like marriages) we rely on legislatures to make fine line distinctions within areas of gray. The bottom line is that this argument is extremely effective against one who makes the genetic equals okay defense of gay marriages but loses most of its value once that argument is rightfully abandoned, resulting in three stars for this list.