Modern ethics requires that we do not put the possibility of future generation in peril - for instance combating global warming. Every individual has a responsibility to ensure the future existence of the species. Homo-sexual relationships without medical intervention cannot produce offspring and it therefore jeopardising the future existence of the species. While we might excuse this on a small scale it is nevertheless unnatural but in a world with a burgeoning population this is excusable and we have scientists claiming that it is natural because other species exhibit this unproductive behaviour. But what if most of humans were homo-sexual and threatened the future existence of humanity? Would we still justify this unproductive behaviour that contributed to a shrinking human gene pool and with that human extinction?