Do you want to read the sort of thing that people are writing about and calling it science these days. Science was once a way towards empirical knowledge based upon testing sound hypotheses with reproducible experiments. This article entitled Bisexual Species: Unorthodox Sex in the Animal Kingdom - Homosexual behavior is common in nature, and it plays an important role in survival. The story begins with an account of "gay penguins" and moves into a discussion on the evolutionary value of same sex animal behavior.
It appears in Scientific American and seems to be a pack of speculation, just so stories and the bizarre reading of human behavior on to animals. Of course humans now look to animals to see what is acceptable behavior. If you can find some sort of creature doing it somewhere then it becomes plausible for human beings. In fact, if you want to justify just about any sexual configurations - just look to the Bonobos - as they seem to be real freaky primates.
This, for whatever it is, is not the scientific method I learned as a student of science...Of course I was in the Physics and Applied Science departments - not in evolutionary psychology or ethics. In this realm, anything can be explained by such story telling. Just make up a story as to why an animal does such and such and how "it might aid survival." We can do this any time and the animal will not be able to refute the thesis. They can't speak for themselves.
Here is just a sample of some of the just so stories found here. I have added the emphasis in the text.
Such behavior seems to ease social tensions. In Bonobo: The Forgotten Ape (University of California Press, 1997), Emory University primatologist Frans B. M. de Waal and his co-author photographer Frans Lanting wrote that “when one female has hit a juvenile and the juvenile’s mother has come to its defense, the problem may be resolved by intense GG-rubbing between the two adults.” De Waal has observed hundreds of such incidents, suggesting that these homosexual acts may be a general peacekeeping strategy. “The more homosexuality, the more peaceful the species,” asserts Petter Böckman, an academic adviser at the University of Oslo’s Museum of Natural History in Norway. “Bonobos are peaceful.”
In some birds, same-sex unions, particularly between males, might have evolved as a parenting strategy to increase the survival of their young. “In black swans, if two males find each other and make a nest, they’ll be very successful at nest making because they are bigger and stronger than a male and female,” Böckman says. In such cases, he says, “having a same-sex partner will actually pay off as a sensible life strategy.”
This seems to be some very strange logic at work...I am saying nothing here about human sexuality - though it seems that this article is more about this than mere animal behaviors in their natural habitats.