Benjamin Franklin wrote: “... in this world nothing can be said to be certain, except death and taxes.” If we update this for modern times, it might read, “… in this world nothing can be said to be certain, except death, taxes, and that the female love interest of a male actor in a movie will always be much younger than him.” Obviously this isn’t as pithy as old Ben Frank would like, but the sentiment remains true nonetheless.

In an interview with entertainment website The Wrap, actor Maggie Gyllenhaal described recently being told that at the ripe old age of 37, she was too old (and I assume decrepit) to be cast as the love interest of a 55-year-old man. Let’s consider this: Gyllenhaal, who is already 18 years younger than the actor in question, cannot be cast as his love interest because she is too old. I really don’t believe that we stop often enough to consider how absolutely warped the world of Hollywood (and our world) must be for this to occur.

This isn’t an isolated example – it is the rule, not the exception. It isn’t just that this versatile, accomplished, and interesting actor was preposterously rejected for not being more than 18 years younger than the her would-be male co-star. The real travesty is that this sort of disparity has been going on for too long, and has become so insidious that we don’t even question it. We see it as completely normal.

The huge age discrepancies in Hollywood films are not reflected in reality. Yet, it is generally not even a plot point in the movie, unless of course it is the rare occasion where the female actor is older than the male actor – then it’s usually the main plot point. It should not be normal to be taken by surprise that the romantic leads in a movie are of a similar age. We shouldn’t be going to the cinema to watch a movie and finding it refreshing that the female romantic lead is within 15 years of the male lead.

It’s well known that women go from playing the love interest of men, straight to playing mothers of men. There is no in-between for women – they are allowed either the beauty of youth, or to give birth to youth. Male actors, on the other hand, can grow older, and audiences will still perceive them as attractive, fantasise about being them, or both.

When you consider that only 17% of women were the ones behind the scenes of the top 250 grossing movies in 2014, you see why things haven’t changed. We need women of all ages telling the stories of women of all ages.

Maggie Gyllenhaal, by sharing this moment, will make a few more people stop and think. Maybe they will start to take notice of the insidious nature of the beast, and the next time Bradley Cooper (40) co-stars with Jennifer Lawrence (24) or Emma Stone (26), they will try to imagine which 40-year-old woman could have played that part.

It’s not that there is anything inherently wrong with a romance like that between Emma Stone and Bradley Cooper in Aloha, or Emma Stone (still 26) and Colin Firth (54) in Magic in the Moonlight. It’s not that older men aren’t attractive, or that it’s wrong to enjoy watching beautiful young women on screen. And it is not the young women who are the problem.

The problem comes when society is convinced that this one dynamic is the norm, and we accept it as the unchanging reality. By doing that, we are buying into an idea that older women are not beautiful, that older women are not worth watching, and that older women have nothing to offer. And remember, in this case the “older woman” refers to a 37-year-old actress. If you are around this age and reading this (if you aren’t too old to operate a computer), it is doubtful you think of yourself as someone who has nothing left to give.

I, however, have nothing left to give to these movies. I have no interest left in seeing another film where a man in his 40s or 50s is romancing a woman much younger than him. Just because we have seen this repeated throughout history is not a reason to continue. It is a reason to stop.

I would prefer to watch Gyllenhaal in a movie any day of the week than any 55-year-old man with a woman half his age. I want to see how on-screen relationships change when the dynamic isn’t always a very young woman with an older man. What if the movie has the energy of a young woman with a young man? What if it is an older woman with a younger man, and age is never mentioned? I want to see what happens when audiences are given the opportunity to watch sex and love transpire between similarly aged couples. I want to see what happens when we have the chance to watch movies created by women, and are shown women of all ages to appreciate.

Let’s see females leads who have lines next to their eyes from an extra 15 years of laughing. Let’s see women who have loved many times, and have experienced real heartbreak and pain. Let us be dazzled by women who are full of life, after a longer life. And let us never read of another incident where a woman is discarded for having the audacity to age.