Just a few disconnected thoughts:-
I thought the Nature/Nurture debate was settled quite conclusively some years ago by a study (John Hopkins/Kinsey Institute?) of identical twins who had been separated, by force of circumstances, at or soon after birth. Identical twins, of course, share common genetic characteristics; but due to their early separation the samples were nurtured quite differently. The study found a striking correlation in sexual orientation within the twin-sets. Also an uncanny deagree of shared skills, tastes and even career paths.
Anyone who has lived in the country and observed the activities of farm animals in the fields would accept that homosexual activity is the natural choice of a proportion of them.
Those who have been raised in a Christian tradition will know that the only sanctioned sexual activity is that between man and wife. All other activity is sinful, and the letters of St Paul are very specific about homosexuality. Nevertheless, we are all sinners, and who is to judge that some sins are more sinful than others?
Some modern churchmen who have liberal views on Gays put themselves through intellectual contortions to get around this one, but only make themselves sound ridiculous.
Gays who join the armed services and perform their duties well should be respected. But they should not parade their proclivities. The culture of the Services is strongly macho-hetero and this cannot be turned around quickly. Banter about gays is not necessarily homohobic.
We swore allegiance to HM the Queen as our monarch (not C in C). Her secondary duty is Supreme Governor of the C of E, so it would be appropriate for her Services to behave in a broadly Christian way (despite the antics that a seemingly large minority of her churchmen get up to!). I do not believe that the Services need worry too much about snide comments from the Metrosexuals, the Islington pseuds, the Guardianista or the BBC. Values in the shires are more permanent, or at least change very slowly. Ten years ago my rural parish, despite the objections of the then Rector (who was Anglo-Catholic), voted to accept if necessary a lady as his successor as Priest in Charge or as Assistant. Later, they voted against the remarriage of divorced persons in our church save in the most extreme circumstances. I am sure they will not accept a gay priest for many years to come.