On the legal front, how will you feel in court when your FO criticises your failure to brief adequately and to react correctly in circumstances under which the aircraft should be garaunteed to be safe, according to its certification? The rules say any reject up to V1 is safe, so reject you should. He will sound even more convincing from a wheel-chair.
In answer to the point made above concerning the time allowed for the decision to reject, it is true that a certain amount of time is available (it used not to be, in the bad old days V1 was the speed by which you had to have started to reject). However, the time allowed is for taking action, not for considering the efficacy of the action and then taking it. Forgive my not having the figures to hand, but I'm down route and away from the necessary paperwork (an AIC, I think, discusses this at depth... anyone with access could post the relevant definition of V1 here, perhaps?).