Posted seven minutes after zsedersw gave a very valid counter-argument. Typical.
The issue isn't what's normal or abnormal. Sexual desires are what they are and they cannot be changed. Many people, gays and straights alike, have sexual desires and interests that some people would consider "abnormal".
You guys are great at dodging questions and mis representing me. I was speaking scientifically, not from a social standpoint and you both know that.
Of course, it is abnormal from both standpoints to have a sexual interest in animals. Why, then, is it abnormal for humans to have sex with animals if we're, as z put it, "animals"? Pedophiles are abnormal and are subject to psych evals. But scientifically, they should be normal too because as you say, sexual desires are normal. They may have a inborn sexual interest in kids.
Wait... but that's sick! Some may say and I agree. But since sexual desires are "normal", who are we to subject normal people to psych evals? Animal sex would subject people to the same, but sex with persons of the same sex is somehow "different".
Science is doing a good job of giving people excuses.