Evolution <> Sex Ed

Via Pharyngula, there's an interesting article (one of a series of articles) on the American RadioWorks website regarding recent developments in the teaching of science in relation to the whole ID/Evolution brouhaha. I was particularly struck by the following:

A man adds, "But I don't think it should be required to study human evolution if it interferes with a personal belief. It's like sex ed, you don't have to take that. It's personal preference. Same thing. Same concept."

I'm trying to figure out if that's an accurate analogy; are there any distinctions between the two which would make it an invalid comparison? The flaw here I think is a subtle misunderstanding of the primary reason why sex education is voluntary. Sex education is not voluntary because of its potential to interfere with personal beliefs, but rather because of the implicitly moral nature of the instruction. Many people feel that the very act of talking about sex has moral implications, while engaging in more robust discussion (contraception, orientation, etc.) clearly carries normative messages. Reasonable people can disagree about whether its proper for government institutions to be imparting normative messages to children; that's why sex education is voluntary, not because it conflicts with personal belief. Evolution^*, despite protestation to the contrary, doesn't make normative assertions, being "descriptive rather than prescriptive". The fact that the descriptions conflict with some peoples' beliefs is true, but irrelevant. So, question answered, at least to my satisfaction. The analogy draw above falls apart because the argument for why sex education should be voluntary cannot be made about evolution⁺.

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* Gah, I keep wanting to write "evilution"... too much Landover Baptist. + Got it right that time.