"This is a monumental victory. It's fantastic," said Adlyn Teoh, who spent nearly a decade battling to get Malaysian citizenship for her son before deciding to take the government to court.
Although Malaysian men can automatically confer citizenship on children born abroad, women do not enjoy the same right because the constitution only refers to the "father" passing on his nationality.
Parliamentarians voted overwhelmingly in favour of a bill which would give both parents the same rights.
Campaigners said the long overdue amendment would transform lives and could spur other countries to scrap sexist citizenship laws, which break up families, render children stateless and leave women trapped in abusive relationships.
Teoh, president of grassroots organisation Family Frontiers, which campaigns on the issue, said Malaysia's current law created "horrendous" problems for women with foreign spouses who give birth overseas and want to return home to raise their families.
Her son Reis ended up stateless for a while when he could not inherit his father's nationality or hers.
Teoh, 46, a cybersecurity professional, said children like Reis do not have the same rights to free education, healthcare and social services as Malaysian children.
Visas have to be constantly renewed and children may have to leave the country after they become adults.
Teoh estimated the annual cost of school fees, health insurance and other charges could amount to 50,000 ringgit ($11,610) per child.
'MASSIVE WIN'
Although Malaysian women can apply for citizenship for children born overseas, decisions often take years and rejections are common, with no reason given.
Family Frontiers said the reform could benefit thousands of binational families whose numbers are rising as more people spend time working abroad.
Malaysia is one of 24 countries that ban or limit women conferring their nationality on their children.
Catherine Harrington of the Global Campaign for Equal Nationality Rights said the vote could drive change elsewhere.
"This is a massive win for the Malaysian mothers, and a huge step for global efforts to end gender discrimination in nationality laws," she added.
"We're hopeful other countries will be inspired ... and take action."
Harrington said Malaysia's sexist citizenship law had deterred professional women, who had gained valuable experience abroad, from returning home and contributing to the country.
Campaigners said some Malaysian women have also become trapped in toxic marriages abroad because they feared if they returned home they could not bring their children.
LEGAL FIGHT
The mothers' battle for equal citizenship rights made headlines in 2021 when Teoh, five other mothers and Family Frontiers took the government to court.
The High Court ruled in their favour and their children now have citizenship, but the Court of Appeal overturned the High Court's decision in August 2022.
The mothers are challenging the ruling, with the case set to be heard in the Federal Court in December.
The bill passed on Thursday was drawn up after elections in late-2022 yielded a new government, which promised to fix the problem as a priority.
The legislation still needs to be approved by the upper house, but campaigners are hopeful it should go through.
However, the reform will not be retroactive, leaving many children born overseas before 2024 still in limbo.
Patricia Low's two children Ethan, 10, and Grace, 8, are among them. They were born in Ireland but have lived almost all their lives in Malaysia.
"I'm disappointed this will not benefit my own children," said Low. "But this fight is also for future Malaysian women so they never have to go through what we had to."
Human rights campaigners have also criticised several regressive amendments in the bill, including one that will scrap automatic citizenship for children born to stateless permanent residents who were born in the country.
These children will now have to apply for citizenship, which critics say will give rise to intergenerational statelessness.
The government could not immediately be reached for comment.
