Research by Nick Drydakis at Anglia Ruskin University found gay men on average earn 9% less compared to heterosexual men.
However, lesbians on average earn 12% more compared to heterosexual women.
Even in countries in the EU, Australia, Canada and the US, which have the strongest anti-discrimination laws, gay and lesbian people experienced more obstacles in getting a job, earning bias and harassment than their counterparts.
Mr Drydakis said: “Despite anti-discrimination laws in some countries, gay and lesbian employees encounter serious job-market barriers.
“They report more harassment and less job satisfaction than heterosexual employees, and gay men earn less than comparably skilled and experienced heterosexual men.
“Good employer–employee relations are shown to increase job satisfaction for gay and lesbian employees.
“Government can help through campaigns promoting respect and equality of treatment in the workplace and by publishing annual data on progress toward equality objectives.
“Firms should evaluate recruitment and promotion policies to ensure equality of opportunity and should address incidents of harassment.”
The report highlights that fewer than 20% of countries have adopted sexual orientation anti-discrimination laws in employment, and 2.7 billion people live in countries where being gay or lesbian is a crime.
It found that people who are open about their sexual orientation within the workplace are more likely to report higher job satisfaction than those who are not.
In the UK, lesbians earned 8% more than heterosexual women, with the gap increasing to 11% in Germany and 20% in the US.
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