Porn stars and studios have called on Google to help publicise legal ways to buy adult content in an effort to combat piracy.Prominent industry figures said they deserved the same measures as those recently introduced to publicise legitimate music and film sites.
"Google continues to discriminate against the adult industry," actress Angela White said.
The search giant told the BBC it did not want to comment on the concerns.
It recently struck a deal with the music industry in the UK to show links to legal ways to buy music more prominently than before.
Record labels had long complained that a search for something such as "Ed Sheeran album" would offer up piracy links ahead of legitimate sites.
'Taboo'A number of influential figures in the porn industry have told the BBC they want the same kind of deal. At present, the online adult industry is not allowed to buy advertising space on Google's network.
"Google is perpetuating the misconception that the adult industry is not a legitimate industry," said Ms White.
"The adult industry is run like any other professional industry; we pay taxes, create jobs and contribute to the economy.
"How many times a day is the word 'porn' typed into the Google search interface? Mainstream corporations like Google continue to discriminate against the adult industry despite the world being genuinely interested in seeking out pornography.