Her autistic sibling was placed in a care home for almost two decades, while another sister was sent away to a boarding school, and her mother left the family.

The experience turned Jang into a disability campaigner -- and singer-songwriter and YouTuber to boot -- who was elected to parliament in April as one of South Korea's youngest MPs, aged just 33.

Jang stands out in a legislature where 83 percent of MPs are over 50 and only 19 percent are women -- a figure that would place the South at 116th in the latest Inter-Parliamentary Union global ranking.

Now she is taking on the country's deep-seated patriarchy and religious conservatism -- including powerful megachurches that condemn homosexuality -- by drawing up a new anti-discrimination bill.

It would ban favouritism based on sex, race, age, sexual orientation, disability or religion as well as several more unusual criteria such as criminal history, appearance and academic background.

However, over the past 13 years six attempts to pass broad anti-discrimination laws in South Korea have all failed.

"For a long time, parliament has existed as an institution made up of middle-aged, able-bodied men," Jang said.

'Very natural'

Despite its economic advances, South Korea remains socially conservative and Human Rights Watch says discrimination against women and minorities is widespread.

Jang said her family suffered; as well as autism, her sister has intellectual disability -- conditions some blamed when they were growing up on their mother's supposed "sins".

The mother struggled to cope and received limited help from the government or community, and eventually the disabled sister was placed in an institution where Jang alleges residents were mistreated.

Soon afterwards their mother left the family and her father sent Jang to live with her grandparents.

"When I realised my mother had left, I was very sad, but on the other hand, I also thought it was a very understandable decision," Jang told AFP in an interview.

Her mother's experiences, and those of her sister and herself, made feminist campaigning "very natural" to her, she added.

In 2011 she dropped out of the prestigious Yonsei University -- an unconventional decision in a competitive society where college degrees often define lives.

Then, 18 years after the family split up, Jang took her disabled sister out of the care facility to look after her herself.

Jang's 2018 documentary "Grown Up" follows their first months living together again, and on YouTube Jang has consistently called for people with disabilities to live in the community.

Last year Jang joined the left-wing Justice Party and in April this year was among six MPs from the group elected to parliament in a vote that President Moon Jae-in's Democratic Party won by a landslide.

But Jang's bill will struggle to become law.

'It's a sin'

Religious beliefs hold much sway in South Korea, where churches remain an important political space and many evangelicals oppose gay rights.

Pastor Kim Kyou-ho, who leads the campaign group Counter Measure Committee for Homosexuality Problems, insists the Bible says homosexuality is a "sin".

"If anti-gay people's human rights and freedom of speech are violated in the process of protecting the human rights of sexual minorities, we cannot call this democracy," Kim said.

About 40 percent of the country's parliament is Protestant, according to the United Christian Churches of Korea, and few politicians are willing to challenge the religious lobby.

Of 10 MPs who signed Jang's bill last month, only two are from the left-leaning Democratic Party, whose support is crucial.

Activists say the Democrats have failed women, with three party heavyweights currently accused of sexual misconduct, including Seoul mayor Park Won-soon, who took his own life earlier this month.

Jang was one of two female lawmakers who declared they would not attend Park's government-run funeral, and instead called on officials to take action against sexism.

Moon, a former human rights lawyer who once pledged to be a feminist leader, supported an anti-discrimination bill during his ill-fated 2012 presidential run.

But during his successful 2017 campaign he said he "opposed" homosexuality and that "social consensus" was needed before legalising same-sex marriage.

Jang, though, insisted rights issues could not wait.

"The essence of politics lies in making choices, and taking responsibility for your actions and words," she said.

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