The proposition "homosexuality is biologically determined" is nonsense -- from a biological point of view, it is like saying "Colorless green ideas sleep furiously." I have explained this before. You can also find explanations in Gould's The Mismeasure of Man among other places.
Very briefly once again: there is no natural property, homosexuality or eye color, that is always manifested rigidly in the same way regardless of initial conditions and environmental circumstances. All biological (and other) dispositional properties are propensities to manifest some trait in some defined set of circumstances.
Therefore, every trait is both biologically and environmentally determined. You can't even ask how much of each. That is because you never have a phenotype --if we are talking about a trait of a biological organism -- that is manifested in no environment at all. Or in all environments. The answer to the question: is it Nature Or Nuture? is _always_ Both.
I don't know why this elementary and obvious point about biology and philosophy of science is so hard to get through to people, even to leftists. I will hacve publish my paper on the subject. But it won't help. Obviously the ideology behind this one is too strong to break easily.
jks
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