What are we to make of the charge that human biological enhancement technologies are 'unnatural'?

In popular lay discourse, objections to human biological enhancement technologies are sometimes expressed in terms of the charge that they are unnatural. This paper critiques the literal claim that seems to be presented here, namely that such technologies are in some ordinary sense 'unnatural' and that it follows from this they are immoral. Such a conceptual 'nature argument' is unsound. However, the paper contends that this does not mean that the charge of unnaturalness should be dismissed out of hand. Rather, the charge of unnaturalness made by a non-philosophically trained public can be construed as expressive of a general attitude of conservative concern about enhancement technologies. Viewed in this way, the charge invites philosophers to take seriously the underlying empirical concerns that underpin these widespread lay reactions.