Arlene Phillips and Moira Stuart were the focus of ageism claims
The age gap between male and female television presenters may be narrowing, a Radio Times survey has suggested.
It looked at peak-time ITV and BBC One shows every 10 years from 1950 to 2010.
In both 1950 and 2010, the average age of male hosts was 46 years nine months, while women's average ages rose almost eight years to 40 years and two months.
BBC Newsnight presenter Kirsty Wark, 55, said it was "genuinely shocking" that women could still lose out on work due to their age.
The BBC has faced criticism for its lack of older female newsreaders, and a wider debate about the presence of more mature women on television.
The corporation denied accusations of ageism after replacing Strictly Come Dancing judge Arlene Phillips, 66, with former winner Alesha Dixon, 30.
Using Radio Times listings, researchers looked at over 800 performers and presenters on programmes screened from 1900 to 2230 between 10 and 16 April in the years 1950, 1960, 1970, 1980, 1990, 2000 and 2010.
The average age for on-screen women fluctuated between 32 and 42 over the years and the average for men ranged from 38 to 47.
FEMALE PRESENTER AVERAGE AGE
1950: 32 years seven months
1960: 37 years
1970: 32 years eight months
1980: 42 years one month
1990: 34 years six months
2000: 37 years 11 months
2010: 40 years two months
The survey excluded feature films, performers under the age of 18 and, in one case, a programme repeated 17 years after its first broadcast. No more than three people were included from each programme.
Ms Wark said it remained the case that "by and large, the profile of men on television is an older one than that of women".
She told the magazine: "But I don't think this is particularly a BBC issue, it's a broadcasting one, although the BBC obviously gets the brunt of it, and rightly so because it's the onus of a public service broadcaster to reflect back to the country it's broadcasting to."
The 47-year-old actress Amanda Donohoe said there was "a long-standing culture that holds that once a woman gets to 40 she's no longer interesting, which is ludicrous".
MALE PRESENTER AVERAGE AGE
1950: 46 years nine months
1960: 38 years 11 months
1970: 44 years two months
1980: 44 years one month
1990: 45 years 11 months
2000: 44 years seven months
2010: 46 years nine months
But she said that this pressure did not apply solely to women, adding: "If someone like Gordon Ramsay has felt the need to have fillers injected into his face despite all his success and his millions, then that tells us rather a lot about what we've come to."
In 2007, BBC director general Mark Thompson denied that the corporation's decision to remove then-58-year-old Moira Stuart from her regular news slot on Sunday AM was motivated by her age.
In the wake of criticism of the decision, Julia Somerville returned to the BBC as a TV news presenter after an absence of nearly 23 years, and Ms Stuart was brought back to read the news during the Chris Evans Breakfast Show on BBC Radio 2.
BBC newsreader Fiona Armstrong, 53, said that when she began her broadcasting career in the 1980s, the "princess and the frog" phenomenon was common on TV news - a younger female presenter teamed up with what she described as "without being unkind, a fairly un-beautiful man".
She added: "I've certainly sat next to my fair share of frogs in my time - and I've been moved off sofas to make way for younger women.
"In fact, if I'd gone to court every time it happened I'd either be very rich or constantly at my solicitor's."
However, the TV presenter Mariella Frostrup, 47, said stereotyping held back the careers of younger women, too.
She said: "My greatest frustration about getting older is that I haven't changed, but other people's perceptions have.
"I've always maintained that just because you don't look like the back end of a bus doesn't mean you can't have an informed opinion, but it seems I'm only allowed to be serious now that I'm no longer in the prime of my youth."