Its always humorous for the far left nutballs to claim people don't understand science when they can't even point to science to explain homosexual behavior. In fact the opposite is true.
There are many half baked theories from the failed twins study to the fruit fly fiasco to relying on unsupervised questionnaires but it never changes the basic knowledge of science.
Biological sexual reactions are purely preparation for heterosexual sex. No matter how much the pro gay marriage group screams and cries the biological sexual reaction does not change for hetero or homosexual people. Men still produce and ejaculate sperm and women still divert blood to the uterus in anticipation for conception. These are measured and rock solid constants yet despite the evidence the religion of "homosexuality must be genetic" never ceases to draw new members to its flock based purely on faith alone.