Gay\transgender -- not by genetics, not by upbringing, not by choice

I've been reading a little about phenotypic plasticity lately, a trait found in all organisms but spectacularly in insects and plants. It means that how an individual's phenotype (ie physical form) is created from its genotype (ie its DNA) depends on many environmental and other factors.So it is entirely possible that a twin can be different - in fact all identical twins ARE different despite having identical genotypes - as an obvious example, they have different fingerprints, but there are always other subtle differences that enable family members to tell them apart.So, to take a giant and heroic leap in logic, perhaps we should now be looking for a difference in the very early upbringing or even birth of these two children that might have caused a difference in gene expression.

The factors can be absolutely anything from pH, temperature, hormones/pheromones, oxygen levels, presence of competitors or enemies - even physical touching. (!)There's a very readable paper on it here:Page not found – Insects on Plants, Chemical Ecology, and Coevolution

The best counter to the "it's a lifestyle choice" claim from the bigoted is to show them a gay porn site and ask if they can 'choose' to get off on it.