The bill effectively outlaws gay-pride parades and any other public display or discussion of lesbian, gay, bisexual and transgender, or LGBT, sexual orientations. It also bans promotion of pedophilia.
The third and final reading was tentatively set for Wednesday, a spokeswoman for United Russia lawmaker Vitaly Milonov, the bill's main author, told The Moscow Times on customary condition of anonymity.
Following November's first reading of the bill, lawmakers raised the maximum fines for promoting nontraditional sexual relationships. The fine for individuals was raised from 3,000 rubles to 5,000 rubles ($170), and for officials the amount went from 5,000 rubles to 50,000 rubles ($1,725).
The fine for legal entities also increased tenfold, from 50,000 rubles to 500,000 rubles ($17,250), Interfax reported.
Maxim Reznik, a St. Petersburg lawmaker in the liberal Yabloko party, said the bill gives authorities "powerful instruments to put pressure on dissenters" and contains a "corruptive element," local television Neva 24 reported.
The United Russia-dominated St. Petersburg legislative body passed the bill Wednesday by a vote of 31-6, with no abstentions, Interfax said.
St. Petersburg police detained five gay-rights activists protesting the bill Wednesday, Rosbalt reported.
Gay activists in November denounced the bill and called it a pre-election stunt.
Nearly identical legislation was passed in the Arkhangelsk region in September, and lawmakers in the Ryazan region introduced a similar ban in 2006.
Male homosexual relationships were a crime in Russia until 1993.
In 1999, the Health and Social Development Ministry dropped homosexuality from the federal list of officially recognized illnesses.
But most of the populace remains vehemently anti-gay, and politicians and rights groups remain reluctant to stand up for LGBT rights for fear of their own reputations.
Thriving gay communities in St. Petersburg and Moscow have campaigned for years to hold gay-pride rallies, but authorities have thrown out their requests.
Unsanctioned events led to crackdowns by riot police and nationalists.
