Sexual Orientation is not fixed, its changeable, esp. in initial years.

In the West, Christianity classified sodomy (I wish scholars could use the terms that was historically used, and not use 'homosexuality' for sodomy and thus confuse everyone) between men to be unnatural for so long, that in modern West, the entire focus of 'liberating' 'homosexuality' was focussed on proving it to be natural -- which came to mean it was innate and not a choice, as the society believed earlier.

Thus, the modern Western society, goaded by gays, has held that 'sexual orientation' in itself is innate and unchangeable and fixed from birth.

The truth is that, although sexual orientation is innate, it is also affected and influenced by nature uptill a certain age -- the formative years of sexuality. Usually a person has the capability to grow either way -- towards both the genders, but the society intervenes by suppressing one part, so that a person becomes unisexual. Some others, may get fixated on the sexuality that is actually sought to be suppressed if they have a positive experience of it -- and this exclusive fixation may have something to do with the social sanctions against it. Other causes for fixation may be the gender roles -- a queer male who identifies as a 'female' from within, may get fixated on receiving anal sex from men in order to fulfil his/her inner femaleness or femininity.

On the other hand, it may be relatively single sided for a minority of individuals, but for the rest it is double sided, and that is where it becomes a matter of choice. The society tries to influence this choice by creating extreme hostile conditions for one type and forcing the other type on people.

It is because, sexuality is changeable in initial years that there are such extreme social mechanisms, including pressures and rewards in order to force men to become heterosexuals.

Without social intervention, sexuality will remain double-sided and fluid for most men, throughout their lives.