Dragon's Call said:Think about it this way. It might be just another natural way of keeping down population...
Just like diseases exists to keep the population under contorl maybe being gay/lesbian is another way of nature helping keep everything under control. (by the way, I'm not saying gay people are a disease at all, so don't take it the wrong way)
They can still artificialy insemante there sperm with a donor egg, so there still going to be able to make a baby if they want one.