London: A leading gender expert has claimed that more and more women are turning into 'Mean Girls,' and he blames the scarcity of good men as partly responsible for this catty behaviour.

Hugo Schwyzer, a professor of gender studies and history at Pasadena City College, said women are being forced to be more competitive with each other than ever.

He stated this is particularly true in the dating pool -- with fewer 'good' men with marriage potential, women must compromise, while the guys hold all the cards.

This means that there is far more female rivalry, he wrote on website.

Even women's success over men in education and the job market is fuelling the 'Mean Girls' trend.

Though women are delivering higher academic scores than their male counterparts, colleges are limited in female admissions, as they must adhere to rules stipulating a fair 'gender balance'.

"Individual women aren't just being victimized by these preferential admissions policies, but their relationships with their female peers," the Daily Mail quoted Schwyzer as saying.

But the biggest player of all, Professor Schwyzer claimed, is the media, which is breeding a culture of women feeling imperfect.

He cited several major articles that added to this idea.

It includes Lori Gottlieb's article in The Atlantic, for example, that encourages women to settle and marry 'Mr not-Right' while their 'marital value' is at its peak.