Equal pay for equal work seems such a stunningly fair concept, who could argue against it? Well, in theory no one; but the myriad ways not to pay men and woman equally, and to divide that work up and redefine certain parts of it as more valuable, have now been made visible. Women, it is often said, don’t want to do the same jobs as men. We are too balanced, too intelligent, too caring to be so driven.

To even mention pay can be awkward. When I first started writing in this newspaper many years ago I was paid less than half the amount that my male colleagues earned. I didn’t know this until I won a prize and asked for a pay rise. Things changed. At another paper I was told never to disclose my salary as it was more than that of one particularly arrogant male columnist.

This is only one small industry, but the secrecy around earnings is part of the problem when we are trying to work out how the gender pay gap operates. Now an audit, following groundbreaking legislation, is forcing companies to disclose their gender pay gaps and so is finally busting open such secrecy.

It’s not looking good. Nor is it straightforward to decipher all the complex reasons for the pay differentials. First, let’s look at the public sector: councils, government departments, schools and hospitals. This reveals that on average women are paid 14% less an hour than their male colleagues. Overall, two-thirds of councils have pay gaps, as do 90% of NHS trusts. (The gap is defined as the difference in average hourly pay and is then expressed as a percentage of the male earnings.)

One may have hoped that schools and hospitals were places of equality. Far from it. Though 77% of the NHS workforce are women, there are huge pay gaps. For example, the Queen Victoria hospital NHS foundation trust in West Sussex had the worst median pay gap, with women paid an average 59p for every £1 a man received. Three-quarters of the trust’s staff are women, but at the top end of the pay scale the consultants are mostly men. In many public sector jobs, managers and decision-makers are predominantly male and well-paid.

This carries through to our institutions of higher education. Every single university in the Russell Group pays women less on a median hourly rate. Durham University has the biggest pay gap, at 29 %.

Disparity at council level is also shocking. North Hertfordshire district council – whose workforce is 65% women and 35% men – had the worst median gender pay gap, at 34%. And I haven’t even touched on the private sector (Macquarie, 41% gender pay gap; Karen Millen, 49%; Ryanair, 72%; Apple UK, 24%).

Some of this is explained away by choice. Ryanair says not many women want to be pilots: but what is happening at the top of FTSE companies, NHS trusts and councils when the best jobs are going largely to men? I have watched this “clone” recruitment in the media, where a young man is promoted over a young woman because he reminds the boss of his younger self.

Men are seen as always more committed to work, with their families taken care of. Sure, there may not be jobs for life; but there aren’t that many top jobs for women who create life. Pregnancy is a sign of wavering commitment. Despite some advances, a woman’s earnings often drop even if she goes straight back to work after having a baby. Certainly, over her lifetime, becoming a parent will penalise her financially.

This has become more than an issue about equal pay. It is about the unpaid care a woman does, and how that affects her choices. Apart from children, she may have to look after other family members, and this often again means low-paid part-time work.

The pay gap, therefore, is not simply about equal pay for equal work: it’s about trying to minimise the structural inequalities in the system. Part-time workers need to sign up to unions, and we have to stop speaking of part-time work itself as either the destiny of women, or as a sign that women are all less ambitious than men. How is it right to have highly paid men in top roles being served by women who are themselves penalised for having children?

What is perceived as a choice for women is not much of a choice. High-earning women, of course, can pay others to sort out their family lives; at a certain income you can cut out the parental penalty. But that is not most people’s lives.

What is eye-opening about these figures is that the situation in the public sector is not better than it is. It, too, seems to go along with the idea that women don’t want top jobs because they are too stressful. One can almost hear the braying of the high-earning BBC presenters who just believe that men are somehow more entitled to money. Lack of female ambition is perhaps one part of the explanation but, really, in every industry? In every sector?

There is much more we can do about equal pay; but this is also about socialisation, what we think we are worth, and how we ask to be paid. I think girls need to be taught this in schools. For if we carry on as we are, we will see these huge pay differentials persist through our lives, with many women ending up in dire pension poverty.

Publishing this data is one thing, but the culture shift required to equalise the numbers means having a real conversation about them. We should all talk to our co-workers about pay. Ask how much our line manager gets paid. Are the recruitment processes in our place of work fair? Stop being embarrassed about money. Inequality thrives on silence. Break it.

• Suzanne Moore is a Guardian columnist