The United Russia party reportedly designed the "straight flag" after the US Supreme court legalised same-sex marriage last month.
The flag, which depicts the outline of a man, woman and three children holding hands, is accompanied by the hashtag "A Real Family".
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"This is our response to same-sex marriage, to this mockery of the concept of the family. We have to warn against gay-fever at home and support traditional values in our country,” Andrei Lisovenko, deputy head of the United Russia branch in Moscow, told newspaper Izvestia.
While homosexuality is not illegal in Russia, laws prevent the promotion of "nontraditional" sexual relations to minors.
However after reports of the heterosexual flag came to light, Twitter users posted a photograph of a similar flag bearing the symbol of an anti-gay marriage movement in France, casting doubt on the flag's originality.
