An illustration photo of male and female office workers. Photo by Unsplash/Kristina spremo

But women’s earnings tend to stagnate in their mid-30s, while men’s incomes continue rising into their 40s, said Glassdoor, which analyzed data across a 30-year career. As a result, after three decades in the workforce, men earn about 25% more than women.

Chris Martin, senior economist at Glassdoor, attributes the initial 12% disparity largely to "between-role" differences.

Men and women are often "choosing different jobs at different companies in different places," which can influence starting pay, he says.

Industries dominated by women also tend to offer lower wages than those dominated by men. Research has shown that when women enter certain occupations in large numbers, compensation in those roles often declines.

Martin says several factors contribute to the growing disparity. One is the so-called motherhood penalty: women are frequently expected to shoulder a disproportionate share of child-care responsibilities, which can limit "the amount of time and energy they have available to dedicate to their careers."

However, even women without children see their earnings dip in their mid-30s, Martin notes, and by their 50s they still earn considerably less than men.

During this mid-career period, men are more likely to move into higher-paying positions, while women advance at slower rates, Martin says.

Because of gender bias, "there’s a cap on how high women can go" in many organizations before reaching the "glass ceiling," he adds.

Women are also promoted to supervisory roles less frequently than men, says Jasmine Tucker, vice president for research at the National Women’s Law Center.

The 2025 Women in the Workplace report by Lean In and McKinsey & Company showed that 93 women were promoted to manager roles last year for every 100 men.

The report found women underrepresented at every level of corporate leadership, particularly at the top.

Women held 29% of C-suite positions, for example, while just 11% of companies on the 2025 Fortune 500 list were led by female CEOs — a record high. C-suite refers to the top-ranking senior executives in a company whose titles usually start with "chief."

A 2022 study also found that even when women received higher performance ratings than male colleagues, they were still viewed as having less potential for advancement.

Men continue to occupy most executive roles, Tucker says, "and when you’re promoting and when you’re hiring, you tend to hire people who look like you."

Martin says the first step organizations should take to reduce the gender pay gap is to conduct pay equity analyses. This means companies must identify and address situations where women are paid less than male counterparts.

Companies should also provide stronger support for employees with caregiving responsibilities, such as flexible work arrangements, he adds.

"You’re going to see caregivers advance less in the workplace and be less successful, because they have needs that are not being met or accommodated by the organization," he says.