I think sexual orientation is not a perversion or a deviation.

You can’t have a fetish of having gay sex. Perversions are called fetishes or kinks. When instead of the traditional vaginal penetration someone indulges into oral/anal sex, foot play, piss play, role play, BDSM etc, those can be considered perversions or deviations from the traditional way of sex which implies only the act of penetration for reproduction and if I’m not wrong there shouldn’t be much movement when the sexual act occurs (correct me if I’m wrong but from my bible study that’s what I recollect).

There is also the possibility of one individual being bisexual which means he/she is attracted to both genders, men and woman, but under the religious belief of sin they find themselves choosing to not pursue sexual relationships with the same gender as that can be considered a sin or against their religion. This is very similar to people who say that being gay is a choice. It’s not a choice unless you are bisexual and choose to only have sex with one gender.

If you want me to explain my point from above I can answer all your questions about why homosexuality is normal from all the points I mentioned in the previous comment.