So Finland has done it again. Not content with trialling universal basic income, solving homelessness and producing an all-female political coalition, the Nordic country has now introduced one of the most equitable parental leave policies in Europe.

Under new rules, all Finnish mothers and fathers will both get nearly seven months’ paid leave, half of which will be non-transferable, while all references to maternity and paternity leave are being scrapped. That sends a very clear message: all parents, from all types of families, are equal in this endeavour.

Compare this to the UK, where much-trumpeted shared parental leave was first introduced five years ago. Only around three in seven families are eligible (agency workers and those on zero hours contracts are excluded), and of those only about 1% have shared any leave at all. By any reckoning it is, according to Adrienne Burgess of the Fatherhood Institute, “an inequitable and failed policy”.

The gaping hole where fathers should be in the domestic sphere has consequences for women too

The failure of shared parental leave is a failure of government, of business and, unfortunately, of the majority of handwringing progressives. If the government wants a future-proof economy, if we want demonstrably better outcomes for our children, if we genuinely care about closing the gender pay gap, we have to overhaul parenting policy and parenting culture in this country, and we have to start now.

We have a small window of opportunity to revolutionise the lives of millions of families, with the government set to publish its proposals to support families in a white paper this spring, following a consultation.

The government’s silence has been deafening. It has batted away calls for non-transferable leave for fathers from, among others, its own women and equalities select committee, the TUC, the Fawcett Society, Working Families, the UK Women’s Budget Group, the Fatherhood Institute and Maternity Action.

Culturally the fight is also moribund. “Campaigns around fatherhood have all but died in the UK,” complains one longstanding activist. Any mention of fighting for men’s rights, even if those men are fathers hoping to improve the lot of their (majority female) partners, is fraught with difficulty. But we have to change the conversation if we have any hope of creating a more equal future. Yes, feminists, we have to fight for men’s rights – whether they want us to or not.

As things stand, fathers get two weeks’ paternity leave at £148.68 (24% don’t even qualify for that), compared with statutory maternity pay at 39 weeks for women, including six weeks’ “enhanced pay”. According to the lobby group, Families Need Fathers, that’s a 96% “gender support gap”.

If couples are lucky enough to qualify for the fiendishly complex shared parental leave, by the time the co-parent comes to take it there is, if they’re lucky, a couple of weeks of statutory maternity pay left. Mostly it’s unpaid unless the father works for one of the rare progressive companies that does offer enhanced pay for all parents.

In the UK no leave – apart from the statutory two weeks – is earmarked for fathers. Norway introduced a use-it-or-lose it daddy quota as far back as 1993. Sweden, Iceland and Finland all have some form of non-transferable leave for the father. And guess what? It works. In Sweden and Iceland men’s uptake is much higher (around 90%) than it is in Denmark (24%), which doesn’t have a non-transferable fathers’ quota, according to an EU study.

Why should we care if fathers aren’t spending time with their babies? Because a father’s involvement in the early part of their child’s life has demonstrably positive outcomes. Another study of four countries – the US, Australia, the UK and Denmark – found that fathers who had taken paternity leave were more likely to feed, dress, bathe and play with their child in the years after the period of leave had ended. In Britain, dads who took time off at birth were almost a third more likely to read books with their toddlers than those who hadn’t. During a trip to Finland a few years ago I was repeatedly told that the push towards equal parenting was not about the rights of the mother or father, but the rights of the child.

The gaping hole where fathers should be in the domestic sphere has consequences for women too. A 2015 report found 54,000 new mothers lose their jobs across Britain every year. While the gender pay gap is small (if growing) among young women, it widens dramatically as women hit their child-rearing years and still stands at 18.4% for all full- and part-time workers. We are never going to address this until men are as likely to take time off to look after children as women; we won’t end maternity discrimination until both parents are seen as potential baby-creating liabilities.

It isn’t just about parental leave. As every parent knows, organising early years childcare is an expensive headache. The Conservative government often boasts about introducing the (largely Liberal Democrat) policy of 30 hours’ free childcare for three- to four-year-olds. In Finland, by contrast, the state provides universal daycare from the moment a parent returns to work. At its most expensive, the service costs only €290 a month- in London, the average is around £650.

In theory, both parents could share the strain of those early years; in reality, it is more likely to be the woman who reduces her hours, works flexibly, or moves to a less intensive role. According to the Fairness in Families Index 2016, men in the UK make up only 25.8% of the part-time workforce, and spend 24 minutes caring for children for every hour done by women.

By introducing a non-transferable period of paid leave for co-carers, the government could open up the possibility of genuine shared parenting for millions of families. It could send a signal that fathers are valued for something other than income. Ministers could argue that affordable universal early years childcare was an infrastructure investment, worth more than HS2. Instead, parents are likely to be expected to hobble on, carrying the financial burden of raising future taxpayers.

So until a progressive government does step up, companies and individuals will have to kickstart a cultural change. How? Chief executives should be looking at companies such as Aviva, which offers all parents the same amount of paid and unpaid leave and has found it good for employees and good for business. Soon companies may find they haven’t got much choice, as millennial fathers are increasingly willing to move to less well-paid jobs that allow them to be more involved in family life.

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Managers should ask every parent returning to work after having a child what support they need – regardless of their sex. Telling men they are too important to take time off, or questioning their work ethic if they ask for flexible or part-time working, is sex discrimination.

Parents also – wherever it is possible, and sometimes of course it just isn’t – have to take action. A recent UK study found that when a father works flexibly and shares childcare, his partner is almost twice as likely to progress in her career; in Sweden it has been estimated that for every month of leave a father takes, his partner’s earnings increase by 6.7%.

So, dads, if your partner is pregnant and you can afford to take shared parental leave but you don’t; if you are not discussing the possibility of part-time and flexible working for the early years of your child’s life: you are part of the problem. And if you are a mother loth to share “your” maternity leave; if you haven’t asked your partner about sharing the load in the early years: you are part of the problem too.

Sharing parental duties equitably is possible. It’s hard, and it involves negotiation and sacrifice – but if we don’t want to be banging on about the lack of equality in society, on repeat, for decades to come, we all have to want to be part of the solution.

• Alexandra Topping is a Guardian news reporter