Among my theatrical bêtes noires is young actors playing older characters for no good reason. At its best, on those occasions when the young actor in question is talented, this looks peculiar (Lucy Farrett, right, in Twenty Minutes to Nine is a good example of this). At its worst, when the audience is presented with a young person with talcum powder-dusted hair and drawn-on wrinkles, it's laughable and undermines the good work of the rest of the cast. Either way, it's a distraction from the drama and rarely excusable.

If you're a young company putting on a show and you don't have any older actors among your ranks, then opt to stage a play – either an existing piece or one of your own devising – with a dramatis personae entirely composed of young actors. If that doesn't appeal, cast an older actor from outside the group. Either way, your creative ambitions needn't be limited.

I saw plenty of this at the Edinburgh Fringe last month, and although it irritated me whenever I came across it, it did flag up an interesting issue: the lack of performers over the age of 35 (I'm defining 'older' as 35-plus here - please don't get upset with me about it, it's just for the sake of this argument and just for the record, I don't consider 35 old) at the festival, and in particular the underrepresentation of older women performers.

The Fringe is undoubtedly a young person's game and this shouldn't come as a big surprise. A major proportion of the companies at the festival each year are students or recent graduates after all, and the comedy programme is largely composed of bright young things trying to make a name for themselves. Young people are more likely to be ready to put up with the far from ideal living conditions at the Fringe (anyone who has slept in a cupboard or on a kitchen floor in an overcrowded flat to try to keep costs down will know what I'm talking about), and have fewer professional and personal commitments that might stop them from flitting off to Scotland for a month to mire themselves in debt.

In some respects, this demographic make-up is to the benefit of the festival: the enthusiasm of the thousands of young people at the Fringe makes it a very vibrant place, and there's a wonderful buzz that accompanies the discovery of exciting new work and careers taking off. But that's not the whole story. The fact that the Fringe is unfavourable to older theatre-makers and comics means that Edinburgh's arts offering is less diverse than it should be (for more on diversity at the Fringe, see below for producer Steve Roe's excellent blog on the subject) and audiences are missing out on the experience and talents of older artists.

What's even more troubling is that out of the limited numbers of older performers at the festival, women are horribly underrepresented, in both theatre and comedy. Out of the 40 or so shows I saw in Edinburgh in August (not really a fair sample I realise, but enough to allow me to comment anecdotally), I spotted only five women who I would estimate to be over the age of 35, although all but one only just scraped into that category. This compared to around 20 older male performers.

There are probably a number of possible explanations for this disparity, but I fear the chief reason is to do with the fact that in most families, even those in which both parents pursue careers in the liberal arts, it is still the woman who has primary responsibility over childcare, making a month away from home at the Fringe an impossibility. In single-parent families, it's even more difficult of course. That's not to say there aren't female performers who make this work, but they are few and far between. It all makes for a depressingly narrow set of options for female performers and audiences alike, and a situation that I fear is not going to improve any time soon given this government's fondness for budget cuts that affect women disproportionally and make it even harder for them to pursue careers after having children. Looks like I might have to reconcile myself to my old bête noire after all.