Let's say it loudly and clearly: Masculinity is not intrinsically a bad thing. Leadership, courage, pride at excelling in sports, devotion to work, taking care of family are all stereotypically masculine traits and are not considered toxic.
Toxic masculinity is generally related to the need to reject all things feminine, such as showing emotion, being empathetic, and carrying out household chores. Behaviors like dominance, stoicism, championing heterosexuality and violence, have become increasingly valued as manly and corrupt the concept of what it means to be a man.​
A large-scale survey in 2018 by an NGO that advocates for children’s rights found one-third of American boys feel pressure to conform to traditional notions of masculinity.
Some of these are positive — physical strength, strong leadership skills — but boys also feel encouraged to be violent, unemotional, and put down girls or talk about them sexually. The vast majority have heard other boys insulted when they were “acting like girls,” meaning crying or otherwise showing vulnerability. Boys understand such behavior to be, as the report put it, “implicitly unbecoming.”
Traditional stereotypes of men as socially dominant, especially when combined with misogyny and homophobia, is often considered "toxic" because it can promote violence, including sexual assault and domestic violence. The socialization of boys in patriarchal societies often normalizes violence, absolving boys of bullying and aggression with responses like "boys will be boys."​
Between the ages of 6 and 8, when kids develop gender constancy -- the idea that their biological sex doesn't depend on what they do or wear -- girls begin to disavow pink and sparkles and other culturally feminine things. But boys become more ruled by stereotypes. That’s because at this age, kids come to understand the gender hierarchy: boys and boy stuff are more valuable than girls and girl stuff. So both boys and girls reject that which is considered feminine. For girls, that rejection marks internalized sexism. For boys, it’s the seed of toxic masculinity.​
These cultural norms are not just considered harmful to women and to society but to men themselves. Self-reliance and emotional repression are associated with increased psychological problems in men such as depression, increased stress, and substance abuse.