A reply to Gillham on the impairment principle.

The impairment argument claims that abortion is immoral, because it results in a greater impairment to a fetus than other actions that are clearly immoral, such as inflicting fetal alcohol syndrome. Alex Gillham argues that the argument requires clarification of the meaning of greater impairment. He proposes two definitions, and points out the difficulties with each. In response, I argue that while the impairment argument's definition of greater impairment is narrow in scope, it is sufficient for its intended purpose. Broadening its scope to more controversial comparisons of impairment is likely to undermine the intuitive appeal of the impairment principle that the argument is based upon.