LGBT Rights: Why Disgust Matters

LGBT rights persist as a controversial topic politically and culturally, but I wonder if it is really a moral or religious argument at all...   It seems to me that the anti-LGBT stance is one born out of disgust, an evolutionary survival mechanism akin to fear and anxiety, the purpose of which is to protect the individual or community from accidental poisoning, spread of disease, etc. Visit the following links for more on this.

• NIH: Why Disgust Matters 
• Psychology Today: Emotions, Survival, and Disconnection

I can certainly understand the public health risks associated with promiscuity (spread of STDs, including AIDS), which are preventable with safe sex practices, but what public health risk does a monogamous homosexual couple pose that a monogamous heterosexual couple does not?

Our most primal emotions have been codified into a system of morals upon which legal frameworks and religious doctrine have been constructed.  This moral system, conceived at a time when much of our understanding of the world was informed by superstition more so than by science, seems out of sync with our current understanding of science and the physical world in which we live. With LGBT youth representing such a disproportionate fraction of the homeless youth population (20 - 40% nationwide), perhaps it is time for a reexamination of our moral code.