Many years ago, about 4 decades from the ammendment of the American constitution came this concept became so popular in the 1960s - "Reverse Sexism".
Subjugation in the society was birthed initially when there was the establishment of unequal genders!
Before I proceed, sexism according to Merriam Webster dictionary, is "behavior, conditions, or attitudes that foster stereotypes of social roles based on sex"
Sexism at the peripheral is targeted at the female folks and this most times come as a form of oppression, none provision of opportunities and as was the case before in the early twentieth century - 19th Amendment to the U.S. Constitution: Women's Right to Vote (1920). The following was however, noted by ourdocument.gov, "achieving this milestone took a lengthy moment of struggle - victory took decades of agitation and protests"
This type was directed to boys and men, and had it's aim to eliminate the one targeted at the females. Hence in the year 1970, there was more focus and many authors willing to document on the male sexism movement as that of the female was gradually waning, and obviously out of place, thanks to their undying efforts to eliminate such acts towards them.
The concept however, was popularized by this shift and was influenced by author Warren Farrell, who wrote The Myth of Male Power. He emphasized how male gender roles, put men in a disadvantaged position by forbidding them from being seen as caring or having emotion.
From a critical view, the focal point however was not even on the oppression aspect of the concept, but rather focused on the gender roles discrimination.
On the other hand, it should be noted that this concept also have some similarities with reverse racism as they work, not to affirm but correct already existing works of discrimination, (though in my view goes overboard in the act of correction.)
A journal published by Reneé Blank and Sandra Slipp in 1994 conglomerated the testimonies of men, who in their daily lives believed they were discriminated especially with respect to their their sex and race.
This happened in a time where women were admitted more into the work force, and even higher position like the managerial positions.
Other set of people that felt this impact in its heavy force, were the LGBTQ community, which mostly cane from their own gender as they are seen not just as "not measuring up to a human" but as "animals".
These concept like any other, is fraughted with plethora of causes and effects, to be treated in details...