In 1970, three furious feminist tracts dominated the bestseller lists: Kate Millett’s “Sexual Politics,” Germaine Greer’s “The Female Eunuch,” and Shulamith Firestone’s “The Dialectic of Sex.” They, and others who comprised what was then called the “women’s lib” movement, fulminated against male dominance, endorsed sexual liberation and demanded that the nuclear family be smashed.

Their fame has faded, but their influence lives on. Lena Dunham, who has built a persona as a spokesman for women, wondered how any woman could reject the label feminist (a 2016 poll found that 68 percent of American women use the term to describe themselves). Her free-floating contempt for men was evident in a recent tweet: “I’d honestly rather fall into one million manholes than have one single dude tell me to watch my step.”

Note the resentment, even when men are attempting to be kind. Dunham is voicing the 21st-century version of the 1970s slogan: “A woman needs a man like a fish needs a bicycle.” Without denying the beneficial effects of feminism, we are overdue for a reckoning about its missteps. One of those was stoking such bitterness between men and women.

While there is near-universal agreement that women should be treated equally in the workplace and in the family, other aspects of the feminist agenda — such as devaluing marriage — have left women more, not less vulnerable than they were pre-revolution.

In 2012, Katie Roiphe, feminist and mother of two children by different fathers, condemned concerns about single motherhood: “If there is anything that currently oppresses the children, it is the idea of the way families are ‘supposed to be.’ ” That’s the feminist mantra, but “alternative” families work only for a tiny minority. For most women, children and, as we’re coming to understand better with each passing year, men, the traditional family remains the gold standard.

Forty percent of American children are now born to single mothers

It should not be anti-feminist to recognize that men and women do need each other and that, contrary to feminist theories, marriage is a key pillar of stability for both sexes and especially for children. Feminists greeted unwed parenthood and easy divorce as steps on the ladder of liberation. For some it was and is. But the price has been steep. Women are commonly worse off financially after divorce than their ex-husbands. Those who worked before, during or after their marriages experienced a 20 percent decline in income after divorce, compared with men, whose incomes rose by 30 percent.

Forty percent of American children are now born to single mothers. This rate of non-marital births, combined with the nation’s high divorce rate, means that around half of all American children will spend part of their childhood in a single-parent home. Social scientists across the political spectrum agree this family chaos is destructive. In 2017, the poverty rate for woman-headed families with children was 36.5 percent, compared with 22.1 percent for father-only families and 7.5 percent for families headed by a married couple. And abundant data show married adults are happier, healthier and wealthier than singles.

The sexual revolution has scythed through the institution of marriage, leaving millions of women without the love and emotional and financial security that they and their children so need. It hasn’t been a picnic for men, either.

Recent studies about the effects of fatherlessness have revealed that the rise of single-parent (which usually means mother-only) families has had even worse consequences for boys than for girls. Father absence in African-American homes leads to more mental-health and behavioral problems for boys, according to an MIT study by two economists looking at brothers and sisters born in Florida between 1992 and 2002. “Growing up in a single-parent home appears to significantly decrease the probability of college attendance for boys but has no similar effect for girls.” They found other worrisome effects, too. “Fatherless boys are less ambitious, less hopeful and more likely to get into trouble at school than fatherless girls.”

Everything is connected. When more boys are growing up without fathers, there are fewer young men who become the kind of adults women want to marry — educated, employed, non-drug-abusing and not involved with the criminal-justice system. Without the grounding of marriage, men become disconnected from society. Some 22 percent of prime-age men (25 to 54) are not working or looking for work. Unmarried men are over-represented in this group. By contrast, married men with only high-school diplomas are much more likely to be employed than unmarried men with some college or an associate’s degree.

Diseases of despair — alcoholism, overdoses, suicide — have been rising among white, working-class Americans, the very population that has witnessed a steep decline in family stability over the past several decades.

Most women want and need upright, well-adjusted, dependable men to serve as co-anchors of healthy and happy families. The feminist movement was deeply misguided to take aim at marriage. Far from oppressing women, it offers a safe foundation for a full life.

Mona Charen is a senior fellow at the Ethics and Public Policy Center. Her new book,“Sex Matters: How Modern Feminism Lost Touch with Science, Love, and Common Sense” (Crown Forum). is out now.