It's finally time to ring the death knell for traditional marriage. Last week, the Obama administration released a comprehensive report on the status of American women, the first of its kind since 1963. The results are mixed. They have made substantial gains in education but still make 80 cents to a man's dollar, are more likely than men to live in poverty, and are more likely to be stalked or killed by intimate partners. The report also sheds light on the status of the American family – a social unit that has been remade by social liberalism. Conservatives are right: traditional marriage is under attack. But the assault isn't just from gay men and lesbians who want the right to enter into marriages of their own. Heterosexual Janes and Johns are also reshaping holy matrimony: they're marrying later, they're marrying less, and for reasons other than having children. And it's making them (and their kids) happier and healthier.

The average age of marriage for a college-educated woman today is 30 (for a college-educated man, 31). Women without a high-school diploma typically marry at 26. Back in 1950, the average marriage age was 21; now that's right about the time that more women than ever are awarded their undergraduate degrees. Marriage for the middle class in America was then a fairly simple financial arrangement: husband worked to support the family, wife cared for the children and the home. It wouldn't be the worst system if all human beings were worker bees without individual interests and passions. But because some women are interested in the world beyond cooking dinners and changing diapers, and some men don't want to spend their whole lives in offices or factories and instead want to get to know their kids, marriage evolved.

Conservatives, of course, want to ride this thing until the wheels fall off. Never mind that the 1950s-style "traditional family" that they so wholly exhort isn't actually all that "traditional" in the long history of marriage, where women were given away as property from fathers to husbands. Back then, women in many states couldn't open their own bank accounts. Until recently, there were no laws against marital rape, and domestic violence was viewed as a private matter and not one for legal intervention. People who fell outside of rigid gender roles or were poor, non-white or disabled didn't live in Leave It To Beaver fantasyland. Women who had children outside of marriage were whisked away to private homes where their babies were taken from them and put up for adoption; children with disabilities were institutionalised; non-white citizens were routinely barred from political participation and discriminated against with impunity; significantly more children and elderly people lived in poverty than today; and physical and sexual abuse of children was rarely investigated.

Thanks to increased gender equality hastened in no small part by the advent of the birth control pill and the legalisation of abortion, families are better off across the board. Mothers today spend more time with their children than they did in 1965, the height of the female-homemaker family. Fathers also spend more time (and more quality time) with their children than ever before. Working outside the home has mental health benefits: women who work have a higher sense of social competence and lower rates of depression than women who don't. And with sole-breadwinner obligations increasingly loosened, men are freer to take on non-traditional roles as caring dads and attentive husbands, who provide much more for their families than just a pay cheque.

And the more egalitarian the relationship, the better. Couples who share both paid work and housework have more sex. Children of women with college degrees do better in school. Women who are college-educated tend to marry later, and also have lower divorce rates; they are more likely to stay married than women who aren't highly educated and financially independent (quite possibly because women who are self-sufficient don't need to get married for support, and can choose a partner with whom they can have a happy and egalitarian relationship).

Notably, fewer men and women marry today than they did a few decades ago: about 15% of women and 20% of men have never married. In 1970, those figures were 7% and 9%, respectively. More women are also forgoing childbearing – nearly twice as many women have never given birth today than in 1976. And when we do have children, we're doing it later: the average age of childbirth is now 25, compared with 21 in 1970. The teen birthrate is also down significantly: in 1970, the teen birthrate was 69 per 1,000 births; today, it's 48.

Those numbers are no indication that marriage and child-rearing are passé or under-valued – quite the opposite. Marriage, more than ever, is something that more people feel the right to opt out of, which means that those of us who do marry (except those who are shamefully barred from marriage because of their sexual orientation) are opting in, and doing so increasingly because we want to, not because of social obligations. If you believe that marriage can be a good thing for people who choose it, this should be welcome news. Children, too, should be welcome additions and not obligations. The fact that more women and families are delaying childbirth indicates that there's more planning involved, and that women and men are making commitments to familial stability and personal ability before deciding to have kids.

We're still a long way from a gender-egalitarian marital utopia, but traditional marriage is blessedly deceased. With its demise has come a new marriage model that is by nearly every measure better for men, women and children, and is hopefully continuing to improve.

Marriage itself is far from dead. But the traditional conservative vision of it is, and thank goodness for that – it's about time the old thing croaked.