Organised and politicised, the counter-movement unpicks abortion rights, fuels online hate and harassment and encourages domestic violence, researchers say.

"Global progress towards gender equality has slowed across regions, and targeted rollbacks of women's and girls' legally protected rights have significantly intensified," the United Nations warned in a report last year.

- Organised anti-abortion campaign -

Neil Datta, the founder and head of the European Parliamentary Forum for Sexual and Reproductive Rights, identified 120 anti-abortion organisations in Europe and reviewed financial data for 54 of them.

In a report published in 2021, he found that from 2009 to 2018, over $700 million (644 million euro) was given to "anti-gender" campaigns by these groups -- NGOs, foundations, religious organisations and political parties.

They were primarily financed "by the US Christian right, Russian oligarchs and economic and social elites from several European countries", Datta said.

These groups have become "professionalised", he added.

"They now influence parliamentarians and member states' foreign relations. They know how to launch lawsuits."

France's independent state equality council (HCE) in a 2023 report noted a backlash that was impacting "major political decisions in many countries", citing the "historic setback" on abortion rights in the United States alongside similar moves in Poland and Hungary.

In 2022, the US Supreme Court overturned the Roe v Wade ruling -- a landmark judgement that legalised abortion nationwide in 1973.

It said conservative movements have also used messaging on social media to "silence or discredit women."

- History of 'backlash' -

Observers say advances in women's rights have been systematically followed by a "backlash" ever since the 1980s.

The theory was detailed by American feminist Susan Faludi in her 1991 book: "Backlash: The Undeclared War Against American Women."

It describes US conservative movements' strategy following the liberalisation of abortion laws and the first entry of women into the labour market in the 1970s.

Conservative movements blamed feminism for a range of ills including miscarriages, infertility and depression, using incomplete or false statistics to back up their position, Faludi wrote.

The "backlash" theory re-entered the public sphere when Roe v Wade was overturned.

The backlash was seen to surge during actor Johnny Depp's televised defamation lawsuit against his ex-wife Amber Heard, with social media commentators attacking her over her accusations of domestic abuse.

For Faludi, the effect of these campaigns can be seen in the increase in domestic violence during the pandemic, the emergence of "incels" -- a misogynist online subculture -- and "the flood of pornography and cyber-bullying," she was quoted as saying in 2023 by French arts magazine Telerama.

- Domestic violence, incels -

Lucie Daniel, an advocacy expert from the feminist NGO Equipop, called the backlash movement "a very heterogeneous coalition".

"You find states with a very conservative agenda on these issues, far-right organisations, and fundamentalist religious movements," said Daniel, who co-authored a 2023 report on "backlash" with the Jean-Jaures Foundation, a French think-tank.

She said these movements are "particularly well organised, connected to each other and benefit from very generous funding from big conservative figures."

The report said it is vital to "increase funding for feminist associations and movements" to counter the backlash.