You seem to not understand the word 'compatible'.   Maybe you need a Biology lesson.  By your use of the word 'compatible' then a person could be 'compatible' with an animal, as long as that's their 'preference', or water would be 'compatible' with your car's fuel system, as long as that was your 'preference'.   Your focus is on emotion and feelings, and not biological fact.    Feelings or desire does NOT change biological fact.   You are, in typical liberal fashion, distorting language and facts to suit your desires, instead of facing up to the truth of our biology.   Based on your statement that  "Gay men are only sexually compatible with other men", I guess you would also say that pedophiles are only sexually compatible with children?  After all, it's where their 'orientation' leads them, and since you define FACT based upon how a person 'feels Oriented' about something, it therefore must be true.   And regarding Incest, There are Genetic (Biology) incompatibilities (FACT).