Homosexuality

Homosexuality
Is it possible to choose to be gay? If so, how? 

That’s not a question for logic, but of psycho-sexual analysis.

Also, are there any good arguments against homosexuality or gay marriage?

It depends on what you define as good.

I know many people are prone to using bad arguments like "it's unnatural".

That’s a false premise. There are many natural examples of ”homosexual” behavior in Humans and other species.

This type of discussion is usually a no-win type and you can easily lose a friend without regard to whether there are good arguments on either side or both. 

Certainly, homosexuality is one of the current hot topics. Years ago, at a conference, a psychotherapist was asked if religion played a part in homosexuality. In response, he told the story of what he called a very tragic case—a young man of 18 who was raised in a strict Catholic home. The young man had never practiced homosexuality, but reported he had strong feelings in that direction. 

In growing up, he was continuously bombarded with the evil of sex, the evil of his body, the sin of masturbation, the sin of looking at girls sexually. One idea impressed him very much: his priest told him it is a terrible sin to love anything in the universe more than God. 

At the age of 16, he admitted (to himself) that he emotionally loved girls more than he cared about God. The realization devastated him. He felt overwhelmed and crushed by guilt and by the sense that something terrible was going to happen to him because of his evil feelings. By the age of 17, he had lost all capacity to feel anything for girls. By the age of 17 and a half, he found himself looking at men sexually. 

I don’t know of any statistical study, but I would be interested to learn if the religious background of homosexuals would disclose a higher incidence of religious anti-sexual attitude in the home than found in less religious or atheist homes.

I forget where I heard this, but the man said: “Religion taught me sex was the most awful, dirtiest, detestable thing on earth and you should only do it with someone you love.”

Is it possible to choose to be gay? If so, how? 

You could argue so, in two ways:

1) Use equivocation to imply you're referring to homosexuality, when really, you mean the second sense of the word 'gay', which is 'happy'. Yes, you can 'choose' to be happy, by say, ignoring/avoiding negative news, focusing on the 'small things' in life (like watching the sunrise/sunset), etc.

2) Use equivocation to imply you're referring to a homosexual state, when really, you mean 'be gay' as in homosexual acts. You can be straight, but choose to have sex with another man. You can even be asexual and choose to do it.

A legitimate question that is not related to logic, because logic is only interested in the validity of the argument, not its content. I am not a doctor or a psychologist, but I do not see any reason why homosexuality would be unnatural or deviant, it is not a phenomenon that impairs health (physically or mentally), and it also occurs in animals. You can explore the scientific background of homosexuality more with educated people who have studied it.