Part of the answer I think lies in Hesse's personal experiences with Freudian and Jungian psychology. One of the reasons I enjoy Hesse's writings is for its archetypal, mythic, timeless themes which are also found in a lot of Jungian symbolism.
One aspect of this would be the direct integration of male/female into a suprabeing, an uber-hero of transcendence, beyond something so earthbound as sexuallity and pro-creation that tether us to this plane. In some ways, those who are drawn to psychoanalysis, are also drawn to personal betterment, to getting to a higher, objective perspective of their own psyche. Much of Jungian psych. is based on an idea of transitioning, from one state to another (purification, coagulation, the integration of scientific terms into the process of human transcendence).
I just finished Beneath the Wheel, one of his earlier works, and it contains a scene where the main character, Hans, kisses a school age (13, 14 I'd estimate) male friend. It's couched in pre-pubscent innocence and based on friendship, but has overtures of something more, something almost bisexual (he later a has brief physical encounter with a woman). Some would argue that those individuals who have expended personal effort in transcendental practices would be attracted to both women and men as they integrated their animus and their anima and could enjoy expressing either aspect with another person of either gender. Interestingly, Hesse uses an interesting plot turn so that the main character doesn't have to make that choice (I'll leave it at that if you haven't read it) . Maybe that's a cop out so that he doesn't need to make an overt choice, or maybe it's just that Hesse skirts such banal issues.
One last point I'd like to make though regards Hesse repeated themes of cloisters, monasteries, boys' schools, etc. In our modern day, we know that such institutions have always been a haven for those have had to surpress/repress their same sex desires or have aided in creating an inner circle of homosexual behavior.

im not exactly sure but alot of cultures arent as definate as we are when it comes to sexuality, i know this wasnt a cover up for homosexuality because german writers are very open as hesse was, i think the relationship should not be viewed as homosexual or platonic because these terms are flawed in that they put your relationship into a definate spectrum where as in the reality of emotions and feelings there is no spectrum or box to prevent you from feeling. so we tend to feel and not act because we try to institute these boxes in our relations. hesse just simply took away these boxes of conformity (germany is pretty liberal so this is typical for german writers i would assume)

ps these are just my thoughts and may have no bearing on the reality of hesses reasons for diverse rfelationships in his writings

kiky,
sorry...i'll be out of subject...but please tell me...where are you from?

I don't think that there are any underlying homosexual themes in Narcissus and Goldmund or at least not of the kind that is being discusses on this thread. I think some people here just assume too much from the word "love". The love between Goldmund and Narcissus is as intense as it can be between two men without any gay undertones. Narcissus' love is clearly played out in the final chapter as he tells goldmund how he has always fealt about him. It's not like Narcissus is coming out of the closet and proclaiming his secret gay longings to him on his deathbed. That's rediculous.

Seems more likely that the people arguing the gay theme are in fact gay themselves and its just wishful thinking on their behalf that their favorite book contains homosexuality.

Was Herman Hesse a Buddhist? A Christian? A Hindu?

What was he? Does he write about new age stuff? I mean I dont read his books, nor do I want to- a friend of mine loves his books. And I am curious to know why. I wouldnt want to read anything that is misleading to the actual truth.