This post was contributed by Lynne Segal, Anniversary Professor of Psychology & Gender Studies in the Department of Psychosocial Studies. It was originally published on The Guardian’s Comment is Free.

Diane Keaton recalled her mother’s advice – “don’t grow old” – as useless, however pertinent for Keaton’s chosen career as an actress. It’s a truism that interesting roles for older actresses are hard to come by. While signs of physical ageing are routinely played down in leading male actors, who regularly take roles as still vigorous and desirable characters (whether heroes or villains), the opposite applies to older actresses, if they are allowed to appear on screen at all.

Are things changing? It was Keaton herself who seemed to herald a shift when she played in the popular 2003 film about love in later life, Something’s Gotta Give. At the time she expressed astonishment at being offered the role of romantic heroine, at 58, despite being partnered by Jack Nicholson, already a decade older. Yet, in Hollywood, the films that portray older women as desirable remain sparse, with Meryl Streep one of the precious few still allowed to play a romantic lead. Meanwhile, when not excluded, one of the notable ways that older actresses make it on to the screen is playing a character with dementia: Judi Dench in Iris (2001), Julie Christie in Away From Her (2006), Streep in The Iron Lady (2011), Emmanuelle Riva in Amour (2012).

However, if cinema remains grim and forbidding territory for older actresses, television is finally starting to offer them more. To be sure, the majority of shows remain youth obsessed, and older women – with The Golden Girls a striking exception – remain perceived as beyond playfulness and sexual passion.

Still, with a third of our population over 50, and 10 million over 65 – and half of them women – the media has had to give a little. Now along comes the second series of the BBC’s Last Tango in Halifax, with its portrait of the late-life romance of two septuagenarians, Celia and Alan. The channel is planning something similar for next year with Grey Mates, involving a friendship network of pensioners, starring Alison Steadman, Stephanie Beacham and Russ Abbot – all in their mid-60s.

Noting the success of Last Tango, I have been pondering what it tells us about attitudes to bodies, old and young. Celia and Alan may be in the throes of romance, but we typically see them, particularly Celia, in her overcoat. The dynamics of their romance are mostly played out in the kitchen or the countryside, with warm smiles and hugs. There is no reference to their sexual concerns, and the bedroom stays off limits. This is all the more striking because their adult children’s affairs mean there is a continuous focus on sex.

Last Tango upholds one of the last taboos around sex, ageing and the body. Intentionally or not, it suggests that though in love, these oldies are past sexual concerns. Yet our culture has little problem presenting older men’s sexual desire. Nor do older men refrain from eagerly proclaiming this, whether in empirical surveys or in their own words. Much of the most esteemed writing by men mourns not the passing of sexual passion, but possible difficulties in its performance. Whether in the work of Ireland’s illustrious poet WB Yeats or America’s celebrated novelist Philip Roth, older men’s chief fear could be summed up as that of a creature sick with desire, but fastened to a dying animal – the threat of penile failure.

Older women’s erotic life, however, is barely registered, save in certain genres of pornography. In the wake of Germaine Greer or agony auntsIrma Kurtz and Virginia Ironside, the most influential women’s voices tackling old age tend to suggest they are contentedly post-sexual, “free at last” from erotic passion.

Given the complexities of desire, I am sceptical about this apparent gender contrast. I see the media’s endless production of eroticised, young female flesh as feeding a sense of shame attached to older women’s bodies. Any eroticisation of our aged female bodies remains taboo and this is one reason older women, in huge numbers (70% of us over-65s) live alone. Tackling our sexual yearnings, or registering our bodies with anything other than disgust, would indeed be radical. I wait to see it.