A new study has found gay men earn 20% less than straight men, while lesbians earn 33% more than straight women.
The report, by Professor Mark Wooden at the University of Melbourne and Associate Professor Joseph Sabia from San Diego State University, is based on 2012 data from the Australia HILDA Survey, which included responses from more than 10,000 people.
It found significant evidence of wage discrimination against gay men, who are less likely to be employed than their straight counterparts and are also paid a lower hourly wage.
"Employer discrimination is likely a major part of the explanation for these wage gaps, especially in the case of gay men," said Professor Wooden.
The study also found evidence of gay men having greater barriers to overcome in the workforce for career advancement.
Although lesbian women earn at least 33% more than straight women, this does not a reflect an hourly pay advantage, said Dr Wooden.
"Lesbian women, predominantly, the reason why they earn more is because they work more," he told BuzzFeed News. "They don't earn any more per hour."
"One of the big reasons why they work more hours is because they are far less likely to have kids," he added, saying lesbians are also more likely to be employed than their straight counterparts.
The 2012 HILDA survey found only 22% of lesbians aged 30 to 49 had kids, compared to 59% of straight women.
Both bisexual men and women experience a lower wage growth over a ten year period, along with gay men, Wooden said.
The annual earnings of bisexual women are largely the same as heterosexual women, however, they are about 13% to 18.5% less likely to be employed.
Whether or not gay and lesbian people lived with their same-sex partner also affected their earning power.
The study found the pay penalty was exacerbated for gay men who lived with their same-sex partner.
"Gay males who are most likely to be observably gay by employers—those who live with a same-sex partner—face larger earnings penalties than those who are discreet about their sexuality," said Dr Wooden.
However, lesbians who live with their same sex partner enjoy a higher wage growth over the period of their work histories, when compared to lesbians without partners.