In Colombia, they like to tell a joke about the promiscuity of women in this southwestern city near Colombia's lush coffee fields: If you ask a Pereira woman to sit down, she lies down.

These days, however, some Pereira women are carving out a new image for themselves more befitting of a Greek myth than a tasteless joke. In the ancient Greek Aristophanes' antiwar play, Lysistrata, women of several villages withhold sex from their husbands to secure the end of the Peloponnesian War.

In early September, a half-dozen Pereira women decided to withhold sex from their boyfriends -- many of whom authorities say belong to gangs -- until they dropped their weapons and found a new way of life. Now, the man who helped organize this so-called ''sex strike'' in this city of 450,000 says about 100 more women have joined and countless others are sympathizing with them.

''We can't keep talking about how the law is king here when there is no law,'' said Julio Gómez, the strike organizer and the top security advisor for the mayor's office. ``We have to look for alternative solutions.''

And so they have, reaching out to youngsters who have made this the most violent city in Colombia with incentive programs to push for them to hand in their weapons and sex strikes to make them think about their actions.