The English words "morals" and "ethics" are derived from Latin and Greek, where they originally meant "right", "acceptable" or "customary behaviour".
As a young man I associated "morals" with the image of a joyless, narrow-minded, finger-wagging moralist, presuming to tell ME how to behave, and "ethics" with difficult, boring texts.
I have since come to realise that morals (or ethics), or a lack of them, are what determine mine and everyone else's behaviour. Now, it seems to me, that there can hardly be anything more interesting or important.
As children, for our own good, we often need to be told how to behave, but as we mature towards adulthood we should, ideally, be able to take over ever more personal responsibility for our own behaviour. However, we all need moral guidance. Where we get it from is an interesting and important point.
We all have a sense of morals (right behaviour) instilled into us during childhood, through our parents, teachers, peers and society at large. In early adulthood it is usual to question received morality and to arrive at some kind of a synthesis, which we then consider to be our own. Those brought up in or who convert to a particular religion or religious sect will probably adopt, or at least pay lip-service to, much of the morality that goes with it. Although many people never seem to think about "their morals" consciously, but simply accept and behave - more-or-less - in accordance with what is expected by the society in which they live, which in its original sense is all that morality is about: behaving in accordance with what society expects.
Morality (right behaviour) is very much what being human is about. It is the one thing that clearly distinguishes us from other animals, and is inherently associated with heightened levels of awareness, something which is beautifully described symbolically in the biblical story of Adam and Eve:
". . . the eyes of both of them were opened and they discovered that they were naked"
Originally we were as amoral as all other animals, not responsible for our behaviour, because unaware of the consequences. Our dawning awareness brought with it increasing responsibility and morality, not just, but also in respect to sexuality. It was no longer acceptable for men and women to spontaneously follow their animal programming (copulating as the lust took them), but only after committing themselves publicly to mutual responsibility for each other and their off-spring (i.e. marriage). At least, that was the idea - which never caught on entirely and is now being undermined by the recent advent of reliable contraception, safe abortion and social security, which enable people to avoid the natural consequences and responsibilities associated with copulation.
Most animals have their behaviour programmed into them. Only among mammals, particular primates, and most particularly in humans, is there a significant degree of behavioural flexibility. While much of our so-called human behaviour is still programmed into us, a fair proportion is leaned from the group (nowadays, society) in which we are brought up and there is some room for learning and behavioural adaptation throughout life.
Some morality (rules of right/acceptable social behaviour) is essential for the functioning of society and the survival of its members. Our recently acquired heightened level of awareness (symbolised in the story of Adam and Eve) gives us a unique (some might call it, a "divine") potential to modify and change our behaviour. The question is: to what end?
For the reasons given in "Origins & Inadequacies of Biblical Authority" I reject as a matter of principle the authority of "holy scripture". The Bible is of great historical and cultural importance, particularly in respect to morals, but its claim to authority is based on false reverence for the past, the magic power of the written word, and the interests of those who base their own authority and social status on it.
In my view, absolute moral authority lies with each individual, since even when we submit to a higher authority, as I believe we must, ultimately it is always the individual who decides. There is no escaping our personal responsibility for what we do.
Looking at morality as a biologist, its purpose is to facilitate the survival of my genes, to which end, as a male, impregnating as many females as possible does not seem an unreasonable thing to want to do. A female, on the other hand, needs to be very selective about which male she allows to impregnate her. Not only does she want the best available genetic material, she also wants its carrier to care for her and her children over an extended period of time.