sDisclaimer: Where I use the 'God' word, please interpret it as Allah, the Amadlozi (Ancestors), Buddha, God the Father, Hashem, Jesus, Krishna, your preferred Deity, the Higher Self, the Universe – whatever fits your concept or tradition. If you're an atheist, maybe regard it as your highest level of self-control.
Celibacy plays a crucial part in both western and eastern monasticism. The human sex drive is the most powerful of all apart perhaps from the basics of food and drink. So to sublimate (convert for a 'higher' cause), that energy, desire, lust, yearning, drive – call it what you will - is seen by very serious spiritual seekers as essential to attaining higher levels of self and mind control.
In the Hindu tradition, life is divided into four phases or 'ashramas': the first stage being the Brahmacharya (student, learning, development) phase. In its crudest interpretation brahmacharya means celibacy. The student (girl or boy) was/is 'expected' to maintain sexual chastity. In days of yore, that may have happened. But in the modern world, I imagine that masturbation if not actual sexual activity might play a role in the period of either gender's developmental and teenage years.
The second stage is Grihastha. That means married. St. Paul said to those who wished to walk a spiritual path, words to this effect: 'However, if they cannot control themselves, they should get married, for it is better to marry than to burn with passion'. (I Corinthians 7:9 International Standard version of Christian Bible 2008 edition). So provision is made – in many traditions. I believe such a provision could and should be included in the Roman Catholic priesthood today - but that's a topic for another posting.
The third stage is Vanaprastha in which the married individual reaches a point where they no longer have family responsibilities or obligations that will limit them from spending more time in contemplation, prayer, spiritual practice and meditation. Vanaprastha means 'wandering in the forest', which speaks for itself.
The fourth stage (even for previously married people) is called Sannyasa. That's the total irreversible renunciation of worldly obligations and dedicating oneself fully to 'God' or self realisation.
In the case of a monk, nun or priest, the celibacy component is there from moment one, via preliminary (postulant or novice) vows and then irrevocable, 'final' (Naisthika brahmacharya in the Hindu monastic tradition) vows.
My Spiritual Preceptor, Swami Shivapadananda [pictured alongside with me (aged 25)], who was the 2nd President and Spiritual Head of the Ramakrishna Centre of South Africa, defined the highest level of brahmacharya as this: 'If I forget about God for one second, I have broken my brahmacharya'. So celibacy is not about pure physical or even mental sexual restraint. It's about a continuum of self-awareness and mind management. It's a complete shift of focus to keeping the mind absorbed in mantra, prayer, contemplating one's true divine (according to that school) nature at all times. Even when engaged in work, service or other activity.
Bottom line to celibacy is this: It is only the very serious, totally dedicated spiritual aspirant who will manage to sublimate the senses to the point that she or he becomes manager of the mind and not the other way around. This concept may seem strange and attract ridicule from lay people who could regard it as 'abnormal'. But for those who choose to dedicate 100% of themselves to God, it's not abnormal or peculiar at all. Nuns refer to themselves as 'brides of Christ' in the Roman Catholic Christian tradition.
The enormous, if not insurmountable difficulties currently being faced by the Roman Catholic Church appear to be not just a matter of sense control but in many instances, paedophilia. Which is psychologically very different from homosexuality or lesbianism. At the heart of the problem though, is the issue of self-restraint and self-management of the sex impulse. In the context of spirituality, being gay is in no way an impediment to achieving the highest levels of realisation through the same disciplines as monastics or married people who go on to renounce. It is said that the 'soul' is genderless and therefore sexual-preference-less. (Let's not get into a secondary debate on this).
It does raise issues unique to homosexual orientation in that the male monk or priest would be living in a male-dominated environment. i.e. still in 'temptation-fraught' surroundings. The same problem would arise for a gay nun. However, heterosexual, homosexual, it doesn't matter: if the focus is truly on offering the highest sacrifice of oneself and one's desires to God, then the impulses can be slowly managed and converted. To the point where being exposed to what might previously have been a sexual temptation or attractive looking body, will immediately take the mind to God consciousness instead. Because we know that what we 'love' is not that body but something beyond it. This doesn't mean that the celibate can become complacent or ever think they've fully conquered the sexual drive. Sri Sarada Devi (herself a nun) used to say that a monk should look at the feet of the gender to which he (or she, if a nun) is attracted. Perhaps not literally, but meaning: be careful where you allow your eyes to go, because your mind and senses will follow.
There are many techniques for sublimating and re-directing the sexual attention and energies and they're typically acquired over a long period of introspection, practice and mind control. The risk of a 'fall' on the sexual front for a celibate is there so long as she or he is in a human body and has not reached what the philosophers would describe as the pinnacle of self- or God-realisation.
So - if, as and when we're tempted to 'diss' or deride those who have chosen to offer their entirety to God's service, let's remember the difficulties inherent in their choice. Let's also not fall into the trap of tarring hundreds of thousands of genuine, disciplined priests, monks, nuns and devotees, on the basis of the hundreds or maybe even thousands, who have not or do not yet successfully tread that path.