Jejudo, South Korea
I don't have any problems with teaching two theories. I don't have any problems with a biology teacher saying that not everyone accepts the theory of evolution. But then again, I don't have a problem with teaching religion in public schools -- it's there anyway, why pretend it's not?
Abiogenesis is a perfect example where alternate theories should be presented because there is no general consensus on how it happened. Certainly, Panspermia should at least be mentioned though, technically speaking, it's not a theory about how life originated from non-life, it's a theory of how life appeared on Earth. Life from non-life still had to occur somewhere else, so it's more a matter of evading the question.
But what is the alternate theory that you mention?
Intelligent Design Theory does not describe an alternate mechanism for the diversity of life, past or present. Its basic argument is not scientific. By scientific, I mean an explanation, an understanding of wholes in terms of their parts (as opposed to, say, an explanation by analogy). IDT argues that the very possibility of an explanation in this way is unsatisfactory for the diversity of life but their solution to the problem, a Designer, is not a scientific answer to the question.
Now, in the real world, we mix up reductionist and analogical explanations all the time (even in science), but the problem here is that IDT offers no reductionist explanation, it offers nothing more than the analogy, "biology is to the Designer as the watch to the watchmaker" without offering an explanation of how the watch was made.
Still, if the introduction of IDT motivates students to look at the issues seriously, I'm all for it. My concern is pedagogical, not ideological*, when it comes to education. My hunch, however, is that it will be yet another way to shut down critical thinking. I can see no particular philosophical reason for why saying, "God did it," shuts down the next question, "How did God do it?" but that's what seems to happen.
*Some might bristle at my use of this term. But the distinction I'm making here is between scientific and non-scientific modes of explanation, not between truth and speculation.