It shouldn’t be news, but on International Women’s Day it’s worth repeating: The thing that makes someone better or worse at their job isn’t their gender.

I’ve seen it myself across hundreds of interviews for roles in my team. Some men are great working with numbers and so are some women. Some women are great working with people and so are some men. The combination I’m hiring for – people skills and numbers skills together – appears rarely, but in both genders.

The truth – that gender doesn’t affect performance at work – also appears in the data. Women and men are no different in their performance and how they are paid.

That is, until they have children.

After that, when a woman becomes a mum, her career progress stalls, her salary stops growing and a gap opens up. The equivalence in the data disappears.

This means the most important thing businesses can do for gender equality is make it easier for parents to be parents, while still having a good career.

It’s not about fixing women, it’s about fixing the workplace.

The evidence: Women’s careers take a dive when they become mums

The chart below is from a study carried out by economists from Princeton and the LSE. It shows how earnings change after having the first child, separately for men and women, for the UK in grey and the US in black.

Men and women’s pay are pretty much even, right up until having children. But after having kids, women’s pay drops immediately and settles at a lower level for 10 whole years. In the UK, that level is more than 40% lower than men with kids get.

What’s happening is that one career in each set of two parents continues pretty much untouched, while the other stalls and doesn’t recover. And, nearly always, it’s the woman’s career that is sacrificed.

Being a mum doesn’t change a woman’s work-related skills and experience, but it does devalue an hour of her work in the eyes of employers.

The chart below is from a study by economists at the Institute for Fiscal Studies (IFS), this time focused only on the UK. It shows what happens to women’s careers in more detail.

Many women, immediately after having a child, either give up their job or cut the number of hours they work – shown in the top two panels. This has an obvious and immediate effect on their earnings in the bottom right panel.

But the most pernicious trajectory in the chart is the least obvious one. It’s what happens to hourly wages. For women, childbirth marks the beginning of a gradual widening of the gap in how their time is valued by businesses.

This is something that women don’t choose; it’s driven by how employers see them. Being a mum doesn’t change a woman’s work-related skills and experience, but it does devalue an hour of her work in the eyes of employers.

The same pattern is happening in marketing. Although it’s not yet possible to cut data on marketing careers and pay by before versus after having kids, it is true that women’s pay starts to lag behind men when they get to the age of parenthood.

The chart above is from Marketing Week’s 2023 Career and Salary Survey. It shows that male marketers get paid more than women early at every stage of their careers. On average female marketers working full time are paid 16.5% less than men doing the same job.

Women don’t get worse at working when they have a baby, and they don’t need fixing

All of this raises another question – why is it that the value of an hour of women’s work takes a tumble when they have children?

On this, data and analysis by academics is able to rule out some things:

• It isn’t to do with the physical tasks involved with giving birth. Women are mostly recovered by six to eight weeks after the birth, but the effects on a career last 10 years.
• It isn’t because women are suddenly less competent than they were before having kids. To the contrary, psychologists find that being a parent is often beneficial to adults’ cognitive development.
• It isn’t because women don’t believe in themselves enough to be leaders or are cursed with imposter syndrome. Psychologists now believe that everyone gets feelings of mild discomfort when stepping out of their comfort zone. It’s worse for higher achievers, but once environmental factors are taken into account, it happens to men just as much as women.

In fact, the truth is likely to be a lot simpler. Many people just believe women are the ones that should do the childcare, and businesses don’t make it easy for them to do that alongside having a proper career.

This pattern is visible in the chart below. It comes from the study that looked at women’s earnings pre and post having children, repeating the analysis we saw above for the UK and the US across four more countries.

On the y-axis is what the authors call the ‘child penalty’ for women, how much lower women’s earnings are versus men’s 10 years after having the first child. The x-axis is answers to attitude surveys in each of the countries.

The chart shows that in countries where a lot of people believe women should stay home when their kids are at school, women’s earnings are a lot lower than men’s. In countries where less people believe in those traditional gender roles, earnings are closer to parity across genders.

Evolving the workplace so it works for parents of both genders

It shouldn’t be the job of individual women who want to continue their careers to fight against society-wide attitudes that point them in the other direction. After all, at the relevant point in time they’re pregnant or have just given birth.

Instead, businesses that care about diversity and equality can change. We can make it so that women who continue to work can juggle the childcare as well as their job. And we can remove any bias in our policies that reinforce the prejudices around childcare.

Meet the brands who are strengthening their business by standing up for parents

Flexible working is a very obvious first thing to put in place. Senior women in our industry have quite rightly identified this as the most important move. And, post Covid, it is now much more practical to put in place arrangements that allow employees to vary the amount, timing or location of their work. For more information check out WACL’s downloadable pack.

It’s also important to ensure that maternity and parental leave policies are symmetrical. That they offer men that take time off with new babies as much financial benefit as women get. Kids deserve the option to have their dads with them just as much as women deserve the option to go back to work.

The long game is one where bit by bit dads and mums share the job of parenting more and more. Then bit by bit women and men both lead businesses and get paid well. And over time our children build societies with more equal expectations.

That’s a future that’s better for women, men and especially young girls. One that we all should strive for every day of the year.