AMs from four parties (from top left, clockwise): Jane Davidson, Helen Mary Jones, Jenny Randerson, Angela Burns
A warning has been given that the high level of women in the Welsh assembly's is at risk at its next election.
The near-50% number of female Assembly Members could drop below 30% in 2011 amid retirements and changes in party selection procedures.
The Institute of Welsh Affairs (IWA) also identifies women AMs with slim majorities who could lose to men.
The report concludes that the "feminisation of the assembly's style, tone and working pattern is at risk".
In 2003, 30 of the 60 members were women, which rose to 31 after a by-election in 2006.
Now the IWA has warned that the current tally of 28 women AMs is poised to fall to 20 or fewer at the next election.
Labour's women AMs currently outnumber its men by 16 to 10, but the party has stopped using all-women shortlists - although constituency parties choose from a balanced list of men and women.
Plaid Cymru has dropped a policy of putting female candidates first on its regional lists.
Instead, first-placed Plaid candidates must be followed by someone of the opposite sex.
The report highlights seats where sitting female Labour AMs have slim majorities and could be challenged by men.
It estimates a female membership of about 30% would be close to the "critical mass it is generally agreed necessary to ensure that the culture of an organisation remains reasonably feminised".
But the reports adds: "If this trend were to continue in subsequent elections then the boasts of a number of leading politicians, made in the early years of devolution, that Wales was leading the world in achieving gender balance in its politics, will have been short-lived."
IWA Women group chair Professor Laura McAllister said Wales was "in danger of retreating to its traditional male dominance of politics and public life as a result of many assuming the battle is won on gender equality".
"Women remain marginalised in terms of public representation in Wales and the giant strides forward made after devolution look extremely vulnerable after 2011," she said.
Prof McAllister added: "There is an underbelly of discrimination in all aspects of Welsh public life as regards gender, amongst other things.
"The figures for Wales and the National Assembly actually belie some pretty awful statistics in other fields.
"Only eight of our 40 MPs are women and half of those were selected through all-women shortlists.
"Only a quarter of our local councillors are women, 90% of our council leaders are men: need I go on?
"This idea that there's a meritocracy is quite abject nonsense."
Cardiff North Labour MP Julie Morgan said the "important" report showed "we've got to be vigilant all the time about keeping a good gender balance".
"In Labour we've had two selections where women have been replaced by men and I think we've just got to be aware of this when we're doing our next selections and try to make sure that the really good record that we've got in the assembly is kept up," she said.
Wales's first female party leader, Liberal Democrat AM Kirsty Williams, said the Lib Dems had "rejected any form of positive action for women" and were "taking softer measures" to encourage gender balance.
"We've established a diversity fund, which helps women financially if finance is a barrier to seeking selection as well as looking at individual mentoring schemes and we've changed our selection process by which people are approved as candidates...[to make it] very much skills-based rather than experience-based," she said.
"We know that there are very talented women in all political parties and in public life in general who are not getting to the top because there is discrimination within the political process and within political parties.
"We do have to find ways in which we can break through that and make sure women take their rightful place in all aspects of Welsh public life," Ms Williams added.