Yeraza, The reason people come to believe that being gay is natural is because, well think of two consenting samesex people loving each other,.. and if you don't take the literal translations of the bible super literally, aand if you don't think about the need that all relationships should be able to procreate (because lets face it, we have more people than resources as it is, and many poor hetero couples can't anyway)... then it makes perfect sense that we're all humans - and two consenting samesex adults being together seems pretty harmless.
I think that the mentality that makes someone develop a fetish may be innate, addiction for example clearly runs in families,. but the specific object, costume, action or body part they fetishize is learned. Think about OCD. It is an innate characteristic, but that does not mean "washing your hands repeatedly" is an innate characteristic; it is just one way OCD can manifest.