IMO consensual sex between people of any sexual persuasion who are not in a committed relationship does no-one any harm. If folk do not wish to marry, why should they? Even 'promiscuous' sex is only 'wrong' in the eyes of the morally pious. My definition of what constitutes a 'sin' is an action that does harm. Sex is perfectly natural and pleasurable. It isn't a 'minor sin', it isn't a 'sin' at all! I do find it a bit strange, the Church's over-preoccupation with what folk do with their genitals! Surely there are far more hurtful, harmful and evil actions that could be addressed by religious 'rules'?