A commenter who identifies himself or herself as Clutch responded to my post on teaching values without inclusion of religion. Part of the burden of the comment is to argue that one can "mention" God but cannot - and should not - inculcate religion.
I agree. But this doesn't resolve the problem. Current establishment clause doctrine does not merely prohibit proselytization but any speech that can be attributed to the state that, if we use the on-again, off-again Lemon test, inhibits or advances religion or, if we use Justice O'Connor's approach, "endorses" religion or ireligion.
It seems to me that, if government wants to address matters with which religion is concerned, a refusal to acknowledge the way in which the religious beliefs of its citizens relate to those matters is to inhibit religion or endorse irreligion. (You can argue that its not only by arguing that religious folks ought to buy into a public secularity that they do not, in fact, accept and which, scholars tell us, necessarily impacts theological formation.)
To do this - that is to introduce the notion that faith may bear upon, say, decisions about sexual conduct - is to run the risk, under current doctrine, of being seen as advancing or endorsing those religious views - even if one does not make any exclusive (or even nonexclusive) truth claims about them.