If being gay isn't a choice. Is having sex with animals not a choice as well?

Zoophilia, also known as bestiality (although the latter has more negative connotations) is not a sexual orientation, it is a philia.

Somewhere else on this site I explained the difference between a philia and a sexuality, but I forget where it was... I'll keep an eye out for you and link you.

But long story short, humans can have all sorts of philias, from the utterly benign, even sweet (such as agathophilia - love of kindness), to the downright disturbing (coprophilia - love of feces). While philia's often stimulate a love so great it's sexual, they are not considered sexual orientations, like heterosexuality or homosexuality.

(link). From that post:

"A philia is quite narrowly defined, and generally revolves around a specific aspect of an object or individual (the aforementioned 'anthophilia' is an obsessive love of flowers). It's not the same as simply liking the hair color of an individual, it's being exclusively attracted to something.

This, I would say, is the beginning and end of everything that philias have in common with sexual orientations. While still having some parameters (straights exclusively like the opposite sex, gays exclusively like the same sex), the variation within the definition is broad. And within that definition, a straight men might prefer brunette women, but he would never be attracted to a brunette man. This is one reason that there are both straight and gay age-philes."

That comment was in discussion of a philia based on age (pedo-, hebe-, and ephebo-), but I feel the comparison still stands, as sexuality is often (unjustly, IMO) compared to pedophilia, which, like zoophilia, is a -philia, not sexuality.

Back to the question at hand - are -philias a choice? All in all, I'd say not. I don't believe a pedophile, for instance, or a zoophile chooses to be a pedophile/zoophile anymore than a gay man chooses to be gay. The difference between the two lies in victimization. With zoophiles, consent can never be given, and animals are not sentient, ergo any sexual act with an animal is considered rape. Similarly, a child cannot give consent as they are not considered to have adequate intellectual understanding of the act of sex, and so any sexual act with a minor is also considered rape. With sexualities, the acts occur between two consenting adults, generally in a reciprocal, equal-status, loving relationship. There is no such thing as a reciprocal, equal-status romantic relationship between a minor and an adult, because the adult holds all the power. There is no such thing as a reciprocal, equal-status romantic relationship between a person and an animal, because the animal is not sentient.

Hopefully, this will give you something more solid with which to retort the next time this topic comes up.

Actions are choices. Genes and/or external factors in your life, in addition to emotions, are not choices.

I wish you'd have stayed and talked it out with your friend. He's really ignorant. -_-

I think this is actually a very good questions because it challenge our thinking of where do we draw the line for what is conventional and what is socially accepted. I think for our generation specially being gay is increasingly more accepted but still carries a lot of stigma. Sodomy in the other hand is not accepted. Both are not convectional but are seem to some degree as sexual deviation. To me being gay you can't help how you feel but it is kind of beautiful when two people love each other regardless of orientation. Sodomy is disgusting and kind of violates animal rights.