Women are paid more than men until they reach their 40s, according to an official assessment of the gender pay gap.

It found that the difference between wage levels for male and female employees leans in favour of women rather than men among workers in their 20s and 30s.

Twenty-something women have earned more than men in the same age group for the past decade.

Now, in a further sign that the gender pay gap is retreating, the figures show that for the first time women in their 30s are also paid more than their male contemporaries. Men only become better paid when they reach middle age.

Research found that the difference between wage levels for male and female employees leans in favour of women rather than men among workers in their 20s and 30s (stock photograph)

The disappearance of apparent pay bias against women in their 30s comes as growing numbers of women put off having children until later and later ages.

Figures covering last year show that women in their 20s, working full-time and without counting overtime, earned 1.1 per cent more on average than similar men.

The figures, published by the Office for National Statistics in its national hours and earnings survey, also show that women in their 30s out-earned men by 0.2 per cent on average last year.

But a pay gap in favour of men still cuts in after the age of 40. Women in their 40s are paid on average 13.6 per cent less than men, a disadvantage that rises to 18 per cent for those in their 50s.

Girls still earn less than boys until they reach 21. Among 16 and 17-year-olds, boys earn 16.9 per cent more than girls while for 18 to 21-year-olds the gap is 4.8 per cent.

The figures, published by the Office for National Statistics in its national hours and earnings survey, also show that women in their 30s out-earned men by 0.2 per cent on average last year

The continuing pay gap in favour of teenage boys may be connected to the greater academic success of girls, which means most able women will go to university or further education. Women have closed the gap on men under 40 at a time when education, career and home ownership have become the priority over marriage and family for millions.

The average age at which a woman has a baby is now 30 and the proportion who have a baby over 35 has trebled since the 1980s. The traditional gender pay gap is also being challenged among the young high earners of Hollywood.

In June the Mail reported that for her latest film Jennifer Lawrence, 25, is to be paid almost double what her male co-star receives. The Hunger Games actress will reportedly get £12.5million to appear in Passengers, while Chris Pratt, star of Guardians of the Galaxy, will receive up to £7.5million.

In June the Mail reported that for her latest film Jennifer Lawrence, 25, is to be paid almost double what her male co-star receives. The Hunger Games actress will reportedly get £12.5million to appear in Passengers, while Chris Pratt, star of Guardians of the Galaxy, will receive up to £7.5million

In the past, Oscar-winner Miss Lawrence, a vocal critic of the gender wage gap in Hollywood, has been paid less than male co-stars.

The ONS figures were supplemented by a survey by the Press Association news agency, which said that in 2013 a woman aged between 22 and 29 typically earned £1,111 more than a male rival.

Feminist campaigners said companies should close the pay gap at older ages by offering senior jobs to part-time or job-share managers.

Sam Smethers, of the Fawcett Society, said: ‘Sadly the opposite is true. Once you get to a certain level it is a full-time role, which excludes many women from roles they would be perfectly capable of doing.’

But Patricia Morgan, an author and researcher on the family, said: ‘If the pay gap in the 20s and 30s was the other way around there would be bucketloads of experts jumping up and down demanding that we act to address this dreadful inequality. No-one seems to worry about being unfair to men.