In opening his article, Sue notes that the term "man flu" has become so common that it has been included in the Oxford and Cambridge dictionaries and he wanted to "explore whether men are wimps or just immunologically inferior".
Other scientists argue there's too little evidence to say man flu exists.
He added, "Is it that women are more resilient, that they are able to juggle more when they are ill, or is it that they don't have as severe symptoms?"
Still, Klein, who was not involved in the new study, appreciates that Sue is helping to shed light on gender health differences, "which often are ignored".
While the phrase "man flu" started as derision for what is seen as men whining about being sick, researchers say men's immune systems may be weaker than women's and respiratory illnesses may actually hit them harder.
"The point I want to make is that whether males or females suffer more really depends a lot on our age", said Klein, whose own research is referenced by Sue.
The study's conclusions were questioned by the Chair of the UK's Royal College of GPs, Professor Helen Stokes-Lampard: "We're sorry to be the bearer of disappointing news for half the population - but contrary to popular belief, and this article, the vast majority of robust scientific evidence suggests that flu is not sexist and there is no such thing as "man flu".
Also, she found that males are more susceptible to complications and exhibit a higher mortality due to many acute respiratory diseases.
The so-called "man flu" has been a punchline for decades, but according to one expert it may be time to stop taking it lightly.
I wonder who funded this pointless #ManFlu research? 'Lying on the couch, not getting out of bed, or receiving assistance with activities of daily living could also be evolutionary behaviours that protect against predators, ' said Dr Sue.
Sue further supports his claim about hormones by pointing out that pregnant people - who undergo significant hormonal shifts - are more affected by influenza symptoms than women who are not pregnant.
Just in time for flu season, a in the Christmas issue of the British Medical Journal explores the science behind a debate that has annoyed sniffling, coughing men and infuriated women for years.
Quoting evolutionary theorists (and acknowledging the possibility of "author bias"), Sue wonders this: If males burnt up their energies fighting off infections, would it have been a costly distraction from their strategy of attracting sexual partners by growing bigger, stronger and faster?