I'm not letting you get away with that statistic, busker. The vast majority of animals on Planet Earth do not reproduce sexually, they reproduce asexually or through amazingly complex procedures that make the varieties of gender variation we are discussing look silly and small. Your 99% statement is nonsense unless you are talking about the very small number of living organisms that belong to the Craniata, a kind of a small group that are better known as vertebrates and includes an even smaller group, the mammals. Recent estimates suggest that the familiar animals - mammals, birds, crocodilians, lizards, cartilaginous fish and bony fish amount to about only 4 per cent of the 1.5 million known animal species. Since the estimates are that there are vast numbers of unknown animals on Planet Earth these familiar animals only account for between 0.03 and 0.6 per cent of the total. And I'm not even mentioning plants which are certainly alive, reproduce in all kinds of ways and have all kinds of sexes. Nature is really an infinite rainbow with vast variation much of which works a great deal better at reproducing genetic lines than human sexuality does.