A record number of women are serving in parliaments worldwide, but they only account for just over 16% of all MPs.
Rwanda has the highest proportion of female members of parliament
Women have made progress in elections, but "true equality of status" is a long way off, says a report by the Inter-Parliamentary Union (IPU).
IPU chief Anders Johnsson said women were "dramatically under-represented".
Women fared best in Rwanda, Norway and Sweden, but there are no women MPs in nine countries, including Saudi Arabia and Kyrgyzstan.
On average, women made up about 20% of the deputies elected in the 39 countries which held parliamentary elections last year, the IPU report said.
The numbers fall short of UN targets set in 1995 of a minimum of 30% women lawmakers in all parliaments.
Norway led the way for 2005, with women winning nearly 40% of the vote, placing it in third position overall behind Rwanda and Sweden.
Other countries that met UN targets in 2005 include Andorra, Burundi, New Zealand and Tanzania.
1. Rwanda: 48.8%
2. Sweden: 45.3%
3. Norway: 37.9%
4. Finland: 37.5%
5. Denmark: 36.9%
6. Netherlands: 36.7%
7. Cuba: 36%
= Spain: 36%
8. Costa Rica: 35.1%
9. Argentina: 35%
10. Mozambique: 34.8%
The report found that women accounted for only 8% of parliamentarians in Arab states, but Mr Johnsson said it was "an incredible improvement" on a few years ago.
He described the decision to grant Kuwaiti women the right to vote and stand for national office as an "historic victory".
Huge progress was made in countries emerging from conflicts, particularly in Afghanistan, Burundi, Iraq and Liberia where women had been excluded or marginalised from political life, the report added.
The largest gains in 2005 were made in several Latin American countries - in Honduras women's participation registered an 18-point increase to 23%.
A decrease in the number of women was observed in eight countries, and nine countries - mainly Pacific island states and Arab Gulf states - had no women in their national parliaments as of December 2005.