Along parallel lines, a far lower percentage of Republicans than Democrats believe that changing gender roles have made it easier for marriages to be successful (26 percent of Republicans compared with 47 percent of Democrats). Similarly, 36 percent of Republicans compared with 58 percent of Democrats believe changing gender roles have made it easier for women to lead satisfying lives. Fewer Republicans than Democrats (30 to 48 percent) believe changing gender roles have made it easier for men to lead satisfying lives.

The reaction to the A.P.A. guidelines — largely but not exclusively from the political center and right and much of it critical — was swift. Even Gillette has joined the debate with its new television commercial, “We Believe: The Best Man Can Be,” a critique of toxic masculinity:

“It’s been going on far too long,” the narrator declares. “We can’t laugh it off.”

In a Jan. 7 National Review article, “Grown Men Are the Solution, Not the Problem,” David French, one of the most outspoken critics of the A.P.A. guidelines, wrote “We are in the middle of an intense culture war focused around men.”

French went on to ask:

As we survey a culture that is rapidly attempting to enforce norms hostile to traditional masculinity, are men flourishing? And if men are struggling more the farther we move from those traditional norms, is the answer to continue denying and suppressing a boy’s essential nature?

His answer is no:

Male children are falling behind in school not because schools indulge their risk-taking and adventurousness but often because they relentlessly suppress boys and sometimes punish boys’ essential nature, from the opening bell to the close of the day.

He concludes:

We do our sons no favors when we tell them that they don’t have to answer that voice inside them that tells them to be strong, to be brave, and to lead. We do them no favors when we let them abandon the quest to become a grown man when that quest gets hard. Yes, we do them no favors when we’re not sensitive to those boys who don’t conform to traditional masculinity, but when it comes to the crisis besetting our young men, traditional masculinity isn’t the problem; it can be part of the cure.

From a more academic vantage point, Steven Pinker, a professor of psychology at Harvard, replied to my inquiry with a detailed critique of the A.P.A. guidelines.

“The report is blinkered by two dogmas. One is the doctrine of the blank slate” that rejects biological and genetic factors, Pinker wrote, adding that

The word “testosterone” appears nowhere in the report, and the possibility that men and women’s personalities differ for biological reasons is unsayable and unthinkable.

The other dogma, Pinker argued,

is that repressing emotions is bad and expressing them is good — a folk theory with roots in romanticism, Freudian psychoanalysis, and Hollywood, but which is contradicted by a large literature showing that people with greater self-control, particularly those who repress anger rather than “venting,” lead healthier lives: they get better grades, have fewer eating disorders, drink less, have fewer psychosomatic aches and pains, are less depressed, anxious, phobic, and paranoid, have higher self-esteem, are more conscientious, have better relationships with their families, have more stable friendships, are less likely to have sex they regretted, are less likely to imagine themselves cheating in a monogamous relationship.

In Pinker’s view, the A.P.A. guidelines fail to recognize that

a huge and centuries-long change in Western history, starting from the Middle Ages, was a “Civilizing Process” in which the ideal of manhood changed from a macho willingness to retaliate violently to an insult to the ability to exert self-control, dignity, reserve, and duty. It’s the culture of the gentleman, the man of dignity and quiet strength, the mensch. The romantic 1960s ethic of self-expression and escape from inhibitions weakened that ethic, and the A.P.A. report seems to be trying to administer the coup de grâce.

Pinker suggested rather that

One could argue that what today’s men need is more encouragement to enhance one side of the masculine virtues — the dignity, responsibility, self-control, and self-reliance — while inhibiting others, such as machismo, violence, and drive for dominance.

There is a major difference between the two parties regarding the basic nature versus nurture issue that plays such a prominent role in the debate about men. As my Times colleague Claire Cain Miller reported in December, data from Pew shows a partisan divide over whether

gender differences were the result of biology (and thus unlikely to change) or societal norms. More than half of Republicans said biology determined differences in how men and women parented, expressed feelings or spent their free time. About two-thirds of Democrats described society as the primary driver of these differences.

I asked some of those involved in preparing the A.P.A. guidelines for their response to criticisms of the report, including Pinker’s.

Ryan A. McKelley, a professor of psychology at the University of Wisconsin-La Crosse, who participated in some of the research but not in issuing the guidelines, wrote that there was no intent to reject “biological determinants.” Instead, “it was just beyond the scope of those particular guidelines.”

McKelley noted that he keeps “seeing ‘testosterone is missing’ show up in critiques of the guidelines, but psychologists don’t measure or manipulate testosterone levels in patients.”

Similarly, he continued,

If I treat someone for major depressive disorder, it doesn’t matter to me as a clinician what percentage of their depression might have genetic determinants. I can’t change their genes.

McKelley rejected

the implication that the goal is to eliminate male characteristics. The real implication is that rigid adherence to extreme expression of a few select masculine norms is related to poorer health outcomes.

In fact, he argued, the guidelines specifically encourage a kind of competitiveness, citing a section that reads,

Active play between fathers and children has a functional element correlated with several positive child outcomes, such as competitiveness without aggression, cooperation that buffers anxiety, healthy experimentation, social competence, peer acceptance and popularity, and a sense of autonomy.

McKelley said he

would love to have someone argue that “competitiveness without aggression” is somehow undesirable. That sounds exactly like redirecting traits toward more productive activity and behavior.

Edward M. Adams, past president of Division 51 on Men and Masculinities of the American Psychological Association, emailed that the guidelines

espouse positive manhood to include living in cooperation, respect, appreciation, courage, and fearlessness about being fully human. We do not see negativity, shame, unwarranted violence and aggression, gender domination, or hate and prejudice as ways to promote a better quality of life for any one of us.

Adams noted that the guidelines are

a living document and will undoubtedly evolve over time. What is important is that we are grappling with the impact of destructive expectations that may thwart positive development and diminish the physical and emotional health of men and boys.

There is a strikingly different approach to the debate over masculinity in a different branch of academic inquiry. As David Autor, an economist at M.I.T., wrote in response to my query:

The greatest adverse shock to the psychosocial welfare of U.S. men has not stemmed from dysfunctional notions of masculinity (not that these are above reproach) nor from #MeToo (which was long overdue) but from deep secular labor market forces — both technological and trade-induced — that have over nearly four decades reduced the demand for skilled blue collar work.

The effects of these economic changes, Autor wrote, have been devastating:

These forces have dramatically eroded the earnings power, employment stability, social stature, and marriage market value of non-college men. The ensuing dysfunction touches not just in earnings and employment but also male idleness, dysfunctional and destructive behavior (e.g., drug and alcohol abuse), and the erosion of two-parent families, which, research suggests, facilitate children in becoming successful adults.

In a December 2018 paper, “When Work Disappears: Manufacturing Decline and the Falling Marriage Market Value of Men,” Autor, David Dorn, an economist at the University of Zurich, and Gordon Hanson, an economist at the University of California-San Diego, argue that adverse trade shocks, like a surge of imports from China, “differentially reduce employment and earnings of young adult males,” “reduce marriage and fertility,” “heighten male idleness and premature mortality, and raise the share of mothers who are unwed and the share of children living in below-poverty, single-headed households.”