Suppose a a man comes to therapy because for a year he has suffered from sexual impotence. In his thirties and seemingly happily married, shame and frustration are taking their toll. Over time, the jigsaw of his early relations begins to create a coherent picture.

An only child, he was adored by his charismatic and strong-willed mother. Between his parents, there was acrimony. His father, a rather submissive man, received his wife's disparagement without a fight. My patient grew up resentful rather than respectful of his father, and embroiled in his mother's need for him to be the apple of her eye.

Emotional separation from his mother never really happened. Marriage put distance between them but, as his wife said, it felt as if his mother was always there. My patient became more and more like his submissive father - and his wife inevitably began to sound more and more like his disparaging mother.

A few years into their marriage, his sexual impotence became a problem. His emotional passivity worsened. He came to therapy at the request of his wife: "Tell your therapist," she said, "that it's Oedipal, and all about your mother."

She was right, of course. But what does it mean? The term "Oedipal complex" is bandied about as if we are all familiar with what Freud meant. But is it really about little boys wanting to have sex with their mothers and kill their fathers? And what relevance does it have for each and every one of us?

The term was coined by Freud as he embarked upon self-analysis. Associations to his own dreams led him to early memories, including one which was to become the cornerstone of psychoanalytic theory. The memory was of his early infatuation with his mother and jealousy of his father. The ancient story was the myth of Oedipus as told by Sophocles.

Laius and Jocasta, the parents of Oedipus, are told that their son will one day kill his father. To avoid this, they abandon their son. Unknown to them, he is saved and raised by another couple. In time, Oedipus learns from another prophecy that he will kill his father and marry his mother. Believing his adoptive parents are his own, Oedipus flees to avoid acting out these lustful and murderous acts. Tragically, he does unknowingly kill Laius and marry Jocasta, so committing the murder and incest all were so afraid of.

Freud used the story to reinforce his belief that all of us, in our early years, experience both intensely erotic and hateful feelings towards our parents. Because full expression of such feelings is unthinkable, we learn to repress them. Yet they often smoulder on, fuelled by a parent's similar but unacknowledged feelings towards the child. A mother who is unhappy in her marriage may draw libidinous pleasure from her son in a way that prevents his separation. An emotionally absent father may make the child feel both powerful and afraid that his desire to possess the mother may be possible.

As the child becomes adult, the intensity of these early feelings is repressed, yet the pattern of relationship established in infancy is often transferred to others in later life. For my patient, deep intimacy with his mother had always had an uncomfortable edge, and as maternal feelings were transferred on to his wife, these early anxieties were re-activated. Impotence was his unconscious way to maintain some separateness in a pattern that felt smothering. To regain his potency he needed to stand up to his mother, discover his own separate authority and so stop unconsciously repeating his father's passivity.

Freud referred to this process as making "repetitions into memories". It goes to the heart of what he believed the Oedipus story was about: we may be driven by forces we don't understand, which have their roots in infantile emotions, but we can, through reflection, have a say in such habitual repetitions, until they hopefully become at some stage as separate as a memory.

Elizabeth Meakins is a psychoanalytic psychotherapist in private practice. No clinical material refers to specific cases