Sex is an important subject.
Sometimes people say we pay too much attention to it, that there are plenty of other moral problems and that questions of social justice like the exploitation of the poor and ethic minorities, or issues like unemployment should occupy our thinking more and be the focus of moral indignation. Of course, there is a lot in that, but its not a question of choosing one or the other. We should be concerned with both social justice in the political and economic affairs of the world and with personal morality. Both are aspects of discipleship. Christians cannot be loyal to Christ and live carelessly in either respect.