They say that on Mexico City's crowded buses, a young woman could climb aboard a virgin and leave pregnant.
In a city where the manic overcrowding of rush hour does little to dampen the deep-seated male sense of machismo, women learn to dread the constant chat-up lines, the bodies pressed up suspiciously close to theirs, the "dead hand" that just happens to come to rest against their breasts, and worse besides.
Now, though, the women of Mexico City have officially had it. This week, the city inaugurated three bus lines for women only, with plans to add 15 more by April. So far, the experiment appears to be a great success. "With this type of transport, I can dress a little bit better, wear skirts without anyone bothering me," Sandra Jimenez, a 29-year-old commuter, told a reporter from Agence France-Presse. She had previously resorted to taking taxis to work.
The women-only buses have pink signs in the front windows and security guards on board to make sure no male Mexicans – apart from young children and disabled men – try to barge their way on. During rush hour, the dedicated buses pass by every 20to 30 minutes on some of the city's busiest routes.
Mexico City residents take a staggering 22 million bus rides every day, creating an atmosphere ripe for chaos of all sorts.
Officials say about one-seventh of the city's rapes and incidents of sexual harassment take place on buses, but the number of actual complaints is stunningly low – just seven last year.
Every woman has her own defence mechanisms – everything from wearing dowdy outer clothing to carrying a safety pin to deter wandering hands.
Mexico City is not the first place to introduce women-only buses. Similar services already exist in Brazil, Japan and India. The concept is not entirely new in Mexico City either – on the city's underground system, the first three cars are usually reserved for women.
The response in the first few days, though, has been enthusiastic. A couple of times, men have got on a bus, only to be mocked by the passengers and shamed into climbing back off.
"Now he knows how women feel," Yolanda Altamirano, a 64-year-old office cleaner, said after one hapless caballero retreated from her bus.