Research by PWC indicates that just 42% of women in the UK work full-time - 27 percentage points lower than men. Include part-time work and this figure increases to 68% - still a significant lag on the 78% for men. Aside from being a provocative stat, these numbers strike at the heart of gender parity in the UK and serve as a reminder of the work that remains to achieve it.

From a macro perspective, the UK could receive a boost of £170 billion – more than twice the size of the budget deficit– if its female employment matched that of Sweden. This would require not only increasing overall female workforce participation, but encouraging a switch from part-time to full-time work. Part-time roles tend to go hand in hand with slower progression; this, combined with career breaks, are also often pointed to as significant factors underpinning the 18% gender pay gap and fact that women make up just a sixth of senior executives at the largest UK companies.

So why aren’t women working (more)? Theories mainly focus on the pycho-socio-economic context of women: time out of the labour market to have children; their position as primary care givers - for the old and young; as well as factors like women being more likely to forgo career advancement because of family considerations. As with the “Whys”, the “Hows” for fixing it are often equally female focused – better mentoring for women; female only shortlists and quotas; programmes to support transitioning back into the workforce after maternity leave. These measures have had a positive effect, and over the decades there has been a progressive uplift in women working, but what they don't do enough of is address a fundamental imbalance in roles and responsibilities of men and women in the biggest area of life: the home. For a material and lasting solution, are we better off turning the question on its head and asking why men aren’t working less and spending more time in the home?

In the UK, women remain the custodians of the household and family: 76% of mothers say they have primary responsibility for childcare in the home; women also spend 60% more time on housework each week. This role is one acknowledged by both men and women, as well as within the home and outside of it: a 2012 British Social Attitudes study revealed that 69% of men and women surveyed thought the combination of either a mother staying at home and father acting as the breadwinner, or mother working part-time and father working full-time were the preferable ways to organise work and family life with children under school age. A recent Women & Equalities Select Committee report also highlighted that women are predominantly used as the first port of call whenever there are issues outside of the home with child and elderly care. Notwithstanding the fact that women will always give birth, a rapidly ageing demographic and demand for elderly care means rebalancing gender roles at home, particularly with respect to responsibility for care, will be key to ensuring a balance outside of it.

Attitudes are changing: the 2016 Modern Families Index highlights that fathers want, and are, doing more at home, however cultural barriers still limit their participation. The report highlights that whilst younger fathers are open to taking pay cuts to work less, most men still don’t feel confident asking employers for more flexibility.

Thankfully, the government has demonstrated an interest in instigating cultural change in gender roles and female workforce participation. Introduction of 30 hours of free childcare for 3-4 year olds and next year’s measures to introduce tax-free childcare arrangements are steps towards making it more financially feasible to work and pay for childcare. Whilst paid childcare is helpful, it doesn’t necessary alter the status quo of primary responsibility for children in the home, or, importantly, who takes a career break immediately after birth. A measure that does impact this dynamic, however, is parental leave. OECD research highlights that dads who take parental leave are more likely to be involved in childcare in the long term; they are also more likely to contribute and take on a greater share of housework. The Fatherhood Institute has found that for every additional month a father takes parental leave, a mother’s earnings increase by 6.7%.

Last year, legislation was passed which allowed couples to split almost all maternity leave entitlement between them. At introduction, the legislation was hugely popular, with 56% of men supportive. More than a year on and a survey of parents and businesses revealed that just 1 in 100 men are taking it. Why the gap?

Whilst 74% of companies provide more than statutory maternity pay, the same is not true for paternity leave. At £139.58 a week this comes in at below the minimum wage. This means that for most families, fathers taking paternity leave at the expense of a mother taking maternity leave has a hefty opportunity cost associated with it.

In addition to forgone earnings, there is an insufficient push factor in current legislation to overcome cultural norms. Sweden introduced shared parental leave back in 1974, however it wasn’t until the country introduced use-it-or-lose-it paternity leave quotas (and a financial penalty for losing instead of using) that the country saw a seismic shift in uptake of male parental leave. Over the years this allocation has increased, with men now having a 90-day quota. Parents are also rewarded with a bonus payment if half of the overall paternity leave is taken by the dad.

Interestingly, female workforce participation rates in Sweden - and across the Nordic region where shared parental leave has been the norm for decades – is high. In Sweden, 73% of women work, 60% of which is full-time. In Iceland - which tops the World Economic Forum’s gender equality rankings - 80% of its women in work, 61% of which is full-time.

The government has committed to reviewing its Shared Parental Leave in 2018 and in comments to the Women & Equalities Select Committee, former Minister of State for Skills, Nick Boles, said that he would not rule out going further with it. Take-up rates to date, combined with the Swedish example, suggests this would be prudent.

Whilst Shared Parental Leave is not the sole panacea for achieving equality in workforce participation, the role it can play in altering the long-term dynamic of work-care balance, as well as broader social and professional attitudes should not be ignored. As well as representing a significant pool of underutilised economic resources (at a time when the government is trying desperately to solve the UK’s productivity puzzle), the gender gap also entrenches inequality in pay, progression and attitudes towards women in the workplace. Furthermore, as the baby booming generation grow old, and demands on elderly care increase, divisions between male and female roles could be further exacerbated if work-home balances go unchecked. Sweden was 40 years ahead of us in instigating cultural change in this area, hopefully it won’t take us 40 years to catch up.

Verity Ryan is a Public Affairs Adviser and Freelance Political Journalist. The views expressed in this article are those of the author, not necessarily those of Bright Blue.