There was a study on rats that found homosexuality arose when there was overpopulation or overcrowding.  This would make sense of non-procreative coupling from an evolutionary standpoint.  More recently, there was a study that found a biological basis for homosexuality where there was a genetic misfire during fetal development that caused too much of the wrong hormone to be released for that gender:  too much testosterone for a woman, too much estrogen for a man, resulting in the person adopting traits of the wrong gender.  I see no reason why these causative factors cannot be found in the animal world as well.<p>When people describe homosexuality as unnatural, I don&#x27;t believe they are claiming homosexuality is not found in nature.  I believe they mean that the homosexual sex act is not how our sexual organs are supposed to work biologically.