In the last few years various experts have come up with predictions for the 'end of men'.
What they tend to mean is that traditionally male qualities - strength, single-mindedness, machismo - are less important in the modern world. By the 'end of men' they really mean the end of traditional male roles in society.
So what's scary about the latest expert prediction is that she really does mean the end of men. As a gender, we're finished physically, she claims. And it's all down to biology.
What does she mean by the end of men?
The prediction of male extinction was recently made by Professor Jenny Graves, a scientist at Canberra University in Australia, who believes the inherent fragility of male genes has put us on a slippery slope to a man-free world.
She cites the state of male and female chromosomes to back up the theory. The female X chromosome contains a healthy 1,000 or so genes and women have two of them.
Compare that with the male Y chromosome, she says, which started off with as many genes as its female counterpart, but today boasts less than 100. The rest have fallen away over millions of years of evolution.
What's more, men only have one Y chromosome and one X, which means each finds it harder to repair itself than the twin X chromosomes women possess.
"The X chromosome is all alone in the male but in the female it has a friend, so it can swop bits and repair itself,2 said Professor Graves. "If the Y gets hit, it's a downward spiral."
She also described the remaining genes on the Y chromosome as being mostly "junk".
So what does this mean for men? Well, she reckons that in five million years or so 'man' kind will be no more, and women will have won the battle of the sexes in the most fundamental way.
Five million years sounds a decent innings, admittedly, but the worry is that the process is already well under way. Some experts blame chromosomal differences, and the weakness of the Y chromosome, for the difference in average lifespans between men and women.
Other meanings of 'the end of men'
That longevity gap between the genders has also been blamed on male self-destructive behaviour, from drinking and smoking too much to driving fast cars and getting into fights. And what many social scientists believe is that some of these behaviours will get worse as the other interpretation of the 'end of men' comes increasingly into play.
Men won't actually go extinct, but our future looks less than rosy, they say. Women are doing better at school and university than men. The jobs of the future will be increasingly about good communication skills and emotional intelligence, and less about strength and dominance.
"It may be happening slowly and unevenly, but it's unmistakably happening: in the long view the modern economy is becoming a place where women hold the cards," writes Hanna Rosin, author of The End Of Men.
The result is that, already, men are three times more likely than women to take their own lives. They're more likely to be dependent on drugs or alcohol. They're more likely to be unhappy loners without supportive social circles.
In other words, there are now two distinct but overlapping theories about the end of men. In one, we will eventually become extinct because of an inherent biological weakness that already affects our longevity. In the other, men won't die off, but we will become increasingly irrelevant.
Men will bounce back
That's one way of looking at it, at least. But others claim predictions of the end of men are wildly overplayed.
Even in Professor Graves' gloomy scenario, five million years is a long time for medicine to catch up and shore up our dodgy Y chromosome. Professor Graves herself thinks men may not actually die out, but morph into an entirely new species of human, with a new chromosome taking the place of the crumbling Y.
And it seems that men are beginning to address their self-destructive impulses and counteract the effect a weak Y chromosome has on longevity. The latest research suggests that a boy alive now can expect to live to 87. It also suggests that, if current trends continue, in the near future men will have the same life expectancy as women.
Explaining these findings, professor Leslie Mayhew of City University, London, said: "There has been a huge decline in the numbers working in heavy industry, far fewer males smoke than before and there is much better treatment for heart disease, which tends to affect more males than females,"
In other words, the end of traditional male jobs might actually be doing us some good.
Of course, our supposed social and economic irrelevance seems more of a worry, but even here there are signs that men are adapting to their changed circumstances. In some academic areas, boys are beginning to close the gap again with girls at school and college, and unfair though it is, men still earn, on average, 15% more than women in the UK.
On top of that, British psychologist Dr Mark McCormack believes men - and young men especially - are adapting psychologically, too. They're forming more "emotionally rich" friendships and "embracing their softer sides", he says.
So is it the end of men? In five million years, perhaps. But for now, weaker chromosomes or not, it seems unlikely. Many men face grave challenges in the new social and economic order, but slowly, steadily and without fuss (in a very manly way, you might say), men may be starting to bounce back.