The American Psychological Association (APA) officially labeled "traditional masculinity" as "harmful" in a new report.

The label is in the report "Guidelines for the Psychological Practice with Boys and Men," a first of its kind for the association, which was featured in the January issue of Monitor on Psychology magazine.

"Traditional masculinity ideology has been shown to limit males' psychological development, constrain their behavior, result in gender role strain and gender role conflict and negatively influence mental health and physical health," according to an excerpt in the 36-page report.

Citing more than 40 years of research on the matter, the APA defines "masculinity ideology" as "a particular constellation of standards that have held sway over large segments of the population, including: anti-femininity, achievement, eschewal of the appearance of weakness, and adventure risk and violence."

The report claims that adhering to the practice of "masculinity ideology" can hinder the development of adolescent boys by "suppressing emotions and masking distress."

The APA notes a bevy of statistics to emphasize that "traditional masculinity - marked by stoicism, competitiveness, dominance and aggression - is, on the whole, harmful."

The report was developed by numerous experts who worked on it between 2005 and 2018. It is meant to serve as a guidelines for best practice for practicing psychologists.

The report has 10 guidelines featured, one of which urges psychologists to "understand the impact of power, privilege, and sexism on the development of boys and men and on their relationships with others."

The report will expire in 2028, per APA's policy.