David Cameron has defended his pledge to give a third of ministerial jobs in a Conservative government to women.
David Cameron saysMargaret Thatcher set a good example to women
He says he believes it is a "realistic aspiration" to have such high numbers of women in Cabinet and junior ranks by the end of his first term in office.
But ordering all-women shortlists as a way of getting more women involved in politics was "a step too far", he said.
Seven members of Mr Cameron's 30-strong frontbench team are women. Seventeen out of the party's 196 MPs are female.
Mr Cameron told BBC Radio 4's Woman's Hour that his party "does under-represent women".
"What I have said is that it would be my aspiration that by the end of the Conservative government, a third of the ministers of that government would be women," he said.
"I wouldn't set a quota for the Cabinet, but I think that it is right to set that aspiration for the government as a whole.
"If you look at ministers as a whole, that's Cabinet and junior ministers - the whole of the government, which is normally around 100 ministers - the aspiration is one third of them should be women.
"I haven't set a separate quota for junior ministers or Cabinet ministers - I don't believe in that sort of quota setting - but I think it is a realistic aspiration, it's something that I want to achieve as prime minister."
Mr Cameron said the party was "pushing very hard" to get more women from all walks of life to stand as Tory candidates in seats, especially marginals, it needs to win to form a government.
He said 30% of Tory candidates were now women, compared with current levels of one in 10 Conservative MPs being women.
"I didn't want to go for compulsory all-women short-lists - I thought that was a step too far," he said.
"What I have tried - the A-list and a number of other measures - were measures short of that, which were what I call positive action, rather than positive discrimination."
Mr Cameron said the Tories were a party which believes in equal opportunity and "success through merit and your own efforts".
He said the process seemed to show "that there are not enough good women coming forward, not enough getting through to the later stages of selection and then not enough getting selected".
"With organisations like 'Women to Win', we have encouraged more women to put themselves forward," he said.
"We've gone out to find women in various walks of life who would make good politicians and try to encourage them to get on to the list and stand for Parliament...
"I think a lot of people would say there are too many people in politics who are professional politicians.
"To get a broad range of experience from the worlds of business, the voluntary sector, the public services, elsewhere, is a good thing.
"If we exclude women, which the Conservative Party has for too long, you exclude an extremely talented part of the population."
Muslim shadow minister
Mr Cameron cited Margaret Thatcher as a good example of how women can succeed in politics.
"She bust the glass ceiling," he said. "People said it couldn't be done, you couldn't have a woman prime minister. She was not only a woman prime minister, she was an incredibly successful one."
He added that it was also "fantastically exciting" that the Tories had Sayeeda Warsi, the party's shadow social cohesion minister and the first woman Muslim politician in a cabinet of any party.