We are all, to some extent, products of our upbringing. But one must be careful here. It is perfectly fine to reflect upon our upbringing to help understand how that upbringing has shaped our world view, but it is irresponsible to use it as an excuse for bigotry. Forgive me while I digress a bit and offer my own personal anecdote; I will get back to my point.
I was raised in a very strict Roman Catholic home, which has a lot to do with why I have never viewed homosexuality as anything other than a natural variant of human sexuality.
Think about that for a moment.
I just said that I view homosexuality as a natural variant of human sexuality BECAUSE of my strict Catholic upbringing. At this point you may properly ask what it is that I am smoking. You see, when I became a young teen, I would think of sex a fair amount of the time. In fact, all I had to do was hear or read certain words and I would think of sex; words like girl, skirt, leg, outboard motor, etc. But in my Catholic home anything that could even be remotely connected to sexuality was simply never discussed. So I had to learn on my own with no input from my caregivers.
The most influentual source of my education was a weekly series of magazines called, "The Story of Life". It was a 53 week series that explained in clinical but readable detail everything about human life, love, and sexuality. One issue was dedicated to "Lovers of the Same Sex", and it dealt with the issue in a frank and totally non-judgemental manner. Since this was my only real source of information, I had no reason to think that there was a judgement to be made. If I had been indoctrinated at a young age that homosexuality was not a normal variant of human sexuality, it is quite possible that I would not be able to easily adjust my thinking as an adult. In fact, I suspect that most people will find it difficult, as an adult, to rethink what they have been taught are fundamental values. But society's mores are and have always been in constant flux, and each individual's view of what is a fundamental value will sometimes yield, and sometimes not. But as society as a whole becomes more tolerant, more and more people will rise above their upbringing and rethink their values.
The bottom line is that, as a society, we are becoming more liberal, more tolerant, more diverse, and closer and closer every day to our Founders' goal.
Liberty and Justice for all.