Defenders of the permissibility of feticide commonly argue that killing an organism is not homicide unless the organism’s brain has developed enough for it to acquire sentience: the capacity for consciousness and the ability to perceive pleasure and pain. In this paper I will critique one of the more sophisticated versions of this argument that proposed by David Boonin in A Defense of Abortion. In I I will sketch some prima facie problems faced by any appeal to sentience. In section II I will examine Boonin’s attempt to defend an appeal to sentience against these problems by contructing a modified future like ours (FLO) account of the wrongness of killing. I will argue that Boonin’s modified future like ours (FLO) defence of sentience fails. Both his argument for the modified FLO account and his application of this account to feticide rest on ad hoc arbitrary manoeuvres, manoeuvres which mean that the modified FLO account is a plausible criteria for the right to life only if one already grants that feticide is not homicide.