The inevitability of gradualness

The philosopher Peter Singer predicts in the current issue of 'Foreign Policy' magazine:
"During the next 35 years, the traditional view of the sanctity of human life will collapse under pressure from scientific,technological, and demographic developments. By 2040, it may be that only a rump of hard-core, know-nothing religious fundamentalists will defend the view that every human life, from conception to death, is sacrosanct."