There are "simply not enough" women in news and current affairs broadcasting, a committee of peers has said.
Lord Best, chairman of the House of Lords communications committee, said broadcasters needed to make a greater effort to reflect their audiences.
The BBC should do more because of its "special status" and its "dominance" as a news provider, he added.
A BBC spokeswoman said it had taken a "leading role" in increasing the number of women in the industry.
The committee found that, in particular, not enough was being done to get more women working in senior positions in news and current affairs broadcasting.
It said in its report: "Gone are the days when women were seldom heard or seen in news and current affairs broadcasts.
"Nevertheless, in this era of equality, we were surprised and disappointed at how much further broadcasters, Ofcom and the government have to go to achieve genuine gender balance."
The committee, which has members including broadcaster Joan Bakewell, heard evidence from media organisations and individuals for its report.
Lord Best said: "Although on the surface it appears that women are well represented, the facts tell a different story.
"We heard, for example, that men interviewed as experts outnumber women four to one on radio and TV.
"Despite the fact that women make up just over half the population, they are under-represented, both as staff and as experts, in news and current affairs broadcasting.
"And although we recognise the fact that the nature of the sector means that there are additional barriers to women - for example, the fast-paced nature of news which can mean anti-social hours, and freelance work that can make it harder for women with caring responsibilities - the situation is simply not good enough."
Public service broadcasters in particular have to make more of an effort - and especially the BBC because of its "dominance as a provider of news and current affairs", the peer said.
The BBC spokeswoman said: "We have taken a leading role in increasing the number of women in the industry through initiatives like our Expert Women training and our support for women presenters on local radio.
"Nearly half of the BBC's news and current affairs workforce is female, with more than a third in leadership positions.
"While the issues and evidence in the report are based on historical cases, we are always looking at what more we can do and are committed to making further progress."
Recommendations in the committee's report include making working practices "more flexible", taking steps to "eradicate any opportunities for gender discrimination and bullying", and making recruitment more transparent.
In a YouTube video released alongside the report, Lord Best said women "miss out big time" compared with men, and that they can "justifiably feel discriminated against".