The bill would outlaw gay pride parades and any other public display or discussion of lesbian, gay, bisexual or transgender lifestyle, The Moscow Times reported.
The measure equates these acts with promotion of pedophilia, a criminal offense, and stipulates fines of $100 to $150 for individuals and up to about $1,621 for organizations for "public activities to promote sodomy, lesbianism, bisexualism and transsexuality" that children might observe, the local news agency Fontanka.ru said.
The bill passed 37-1 with one abstention in a first reading Tuesday in the St. Petersburg legislature, dominated by the United Russia party, and needs to pass on two more readings.
"The rising popularity of sexual deviations influences our children in a negative way," said the bill's author, Vitaly Milonov, a United Russia deputy.
Gay rights activists criticized the measure and had one-person pickets, the only protests that don't require authorities' permission. They said they would appeal to the European Court of Human Rights.
Igor Kochetkov, head of the LGBT group Vykhod (Exit), called the bill an attempt to tap into homophobic sentiment before Dec. 4 State Duma elections.
"The bill is passed before elections to boost the popularity of United Russia, which is flagging in St. Petersburg," Kochetkov said. "This bill smacks of the Middle Ages."